Sqoop achieves high throughput in data transfer using the Direct Mode, which allows direct communication between the Sqoop client and the database, bypassing the need for intermediate storage in Hadoop. This results in faster data transfers with reduced latency.

The feature of YARN that helps in improving the scalability of the Hadoop ecosystem is Horizontal Scalability. YARN allows for the addition of more nodes to the cluster, providing horizontal scalability and the ability to handle larger workloads efficiently.

The tool used for simulating cluster conditions on a single machine for testing is the MiniCluster. It allows developers to test their Hadoop applications in a controlled environment, simulating the behavior of a Hadoop cluster on a local machine for ease of debugging and testing.

MRUnit is a Java-based framework commonly used for unit testing in Hadoop applications. It allows developers to test their MapReduce programs in an isolated environment, making it easier to identify and fix bugs before deploying the code to a Hadoop cluster.

The concept of Data Localization is crucial in designing a Hadoop cluster. It involves placing data close to where it is most frequently accessed, reducing latency and improving overall system performance. Efficient data processing and resource utilization are achieved by strategically placing data across the cluster.

For advanced Hadoop clusters, Apache Spark is a technique used to enhance processing capabilities for complex data analytics. Spark provides in-memory processing, iterative machine learning, and interactive queries, making it suitable for advanced analytics tasks.

Apache Oozie integrates with other Hadoop ecosystem components, such as Hive and Pig, through Action Nodes. These nodes define specific tasks, such as MapReduce, Pig, or Hive jobs, and orchestrate their execution as part of the workflow.

The Fairness of a Hadoop cluster indicates the balance of load across its nodes. It ensures that each node receives a fair share of tasks, preventing resource imbalance and improving overall cluster efficiency.

The module in Apache Spark specifically designed for SQL and structured data processing is Spark SQL. It provides a programming interface for data manipulation using SQL queries, enabling users to seamlessly integrate SQL queries with Spark applications.

The correct option is 'SLA (Service Level Agreement).' In advanced Oozie workflows, SLA is used to manage job retries and error handling. It provides a mechanism to define and enforce performance expectations for various jobs within the workflow.