Deferred execution in LINQ refers to postponing the execution of the query until the query result is actually enumerated or iterated over. This allows for optimizations and better performance, as the query can be composed and optimized before execution.

A DataSet is a memory-resident representation of data that provides a consistent relational programming model. It can contain multiple DataTable objects, representing tables with data, and allows you to establish relationships between these tables. Thus, a DataSet is used to represent a collection of related tables.

LINQ to SQL allows interaction with data stored in relational databases, such as SQL Server. It provides an object-oriented approach to working with database entities and querying data using LINQ queries.

Deferred execution in LINQ to Entities means that the execution of a LINQ query is delayed until its results are needed. Instead of executing the query immediately when it's defined, LINQ to Entities postpones the actual execution until the query results are iterated or enumerated. This deferred execution allows for optimizations and flexibility in composing complex queries, as the query isn't executed until all the necessary conditions and transformations are in place.

Data binding expressions in ASP.NET are a powerful feature that allows developers to declaratively bind data from a data source to server controls or properties. These expressions, often denoted by <%# %>, enable dynamic and flexible data presentation on web pages. By using data binding expressions, developers can easily connect UI elements with underlying data sources, enhancing the interactivity and functionality of ASP.NET applications.

In Entity Framework, a DbContext is a lightweight representation of a database context. It represents a session with the database, allowing developers to query and save data. DbContext is part of the Entity Framework Core and provides a high-level abstraction for interacting with the database.

In SQL Server, stored procedures can have parameters that can be defined as either input parameters, output parameters, or both. Input parameters are used to pass values into the procedure, while output parameters are used to return values back to the caller. Optional parameters are not directly supported in stored procedures but can be simulated using default parameter values.

The Where operator is commonly used to filter data in LINQ to Entities. It allows developers to specify conditions that must be met for entities to be included in the result set, enabling precise filtering of data based on various criteria.

Option 1, "Connection Strings in App.config," is the preferred method for storing sensitive database connection details separately from the code. By placing connection strings in the application configuration file (App.config), you can easily manage and update them without modifying the source code. This approach enhances security by keeping sensitive information, such as usernames, passwords, and server addresses, out of the codebase, reducing the risk of exposure. Additionally, it allows for flexibility in deploying applications across different environments, as configurations can be tailored accordingly.

LINQ to Entities provides a language-integrated query experience in C# using Lambda syntax. This allows developers to write queries directly within their C# code, making it easier to work with data retrieved from the database. It abstracts the underlying SQL syntax and provides a more intuitive way to query and manipulate data from entity data models.