The correct option is option 1, When you want to create a new DataTable from the DataView. The ToTable() method in ADO.NET is used to generate a new DataTable containing the same data as the DataView. This is helpful when you need to work with the DataView's data in a DataTable format for further processing or manipulation.

One of the key advantages of the DataList control is that it supports multiple templates for item presentation. This feature allows you to define different layouts for different types of data items within the same control. For example, you can have separate templates for displaying header, footer, and individual data items, providing flexibility in the presentation.

When optimizing performance in Entity Framework applications, reviewing query execution plans and indexing strategies is crucial. These aspects directly affect how queries are executed against the database and how efficiently they utilize indexes. By optimizing query execution plans and indexing strategies, you can significantly improve the performance of database operations in your Entity Framework application. This involves analyzing the SQL queries generated by Entity Framework, ensuring appropriate indexing on database tables, and fine-tuning the database engine's execution plan to leverage indexes effectively.

Entity Framework supports CRUD operations which stand for Create, Read, Update, and Delete. These operations enable developers to interact with database records effectively.

ADO.NET provides the ConflictHandling event to customize conflict resolution logic. This event allows developers to define custom conflict resolution strategies when updating data from a data source. By handling this event, developers can implement logic to resolve conflicts that arise when multiple users attempt to modify the same data concurrently.

An Entity Data Model (EDM) in LINQ to Entities represents the conceptual model of data in a database. It defines the structure of the data and the relationships between entities. EDM provides a higher-level abstraction over the database schema, allowing developers to work with entities and relationships rather than tables and columns directly.

Common strategies for handling data conflicts in ADO.NET include implementing manual conflict resolution where the user is prompted to resolve conflicts, or automatic conflict resolution where predefined rules or custom logic resolve conflicts without user intervention.

The method used to create a DataView from a DataTable in ADO.NET is DataTable.DefaultView(). This method returns a DataView object representing a customized view of the DataTable, which can then be manipulated and used for various data operations such as sorting, filtering, and navigation. It provides a convenient way to work with subsets of data within a DataTable.

The Fill method of the DataAdapter is used to populate a DataTable or a DataSet with the result set of a SQL query. It efficiently retrieves data from the database and populates the specified DataTable with the result set, making it suitable for populating a DataTable with the result set of a complex SQL query in a .NET application.

In LINQ to DataSet, the GroupBy clause is used to group records based on a specified key. By grouping sales data by product category, you can then calculate the total revenue for each category. Thus, using GroupBy followed by an aggregation function like Sum allows you to achieve the task of calculating total revenue for each product category.

In LINQ to DataSet, the join clause is used to combine data from two or more data sources based on a related column between them. It allows you to perform operations similar to SQL joins, such as inner joins, outer joins, and cross joins, to retrieve and process data from multiple tables or collections simultaneously. Understanding how to use the join clause effectively is essential for querying and manipulating data using LINQ to DataSet.

To implement a custom conflict resolution strategy in an ADO.NET application, you should handle the RowUpdating event. This event occurs before changes are sent to the database during an Update operation. By handling this event, you can examine the changes being made and implement your custom logic to resolve conflicts before they are applied to the database.