What should you identify?

HOTSPOT
You plan to create several .NET applications that will read from Microsoft SQL Server 2014 databases by using
Microsoft ADO.NET.
The relevant requirements for the applications are described in the following table.

Typically, the applications will read thousands of rows of data at a time.
You need to identify which object to use to retrieve data for each application. The solution must minimize the
amount of memory used on the application server.
What should you identify? To answer, select the appropriate options in the answer area.
Hot Area:

Answer:

Explanation:
App1: DataReader
App2: DataReader
App3: DataAdapter
Need to use a DataAdapter since the data could be modified.
Note:
You can use the ADO.NET DataReader to retrieve a read-only, forward-only stream of data from a database.
Results are returned as the query executes, and are stored in the network buffer on the client until you request
them using the Read method of the DataReader. Using the DataReader can increase application performance
both by retrieving data as soon as it is available, and (by default) storing only one row at a time in memory,
reducing system overhead.
A DataAdapter is used to retrieve data from a data source and populate tables within a DataSet. The
DataAdapter also resolves changes made to the DataSet back to the data source. The DataAdapter uses the
Connection object of the .NET Framework data provider to connect to a data source, and it uses Command
objects to retrieve data from and resolve changes to the data source.
https://docs.microsoft.com/en-us/dotnet/framework/data/adonet/dataadapters-and-datareaders