Which class should you use?

You are an enterprise application developer. You are creating a component to load data from Microsoft SQL Server database tables into combo boxes. The retrieved data has a numeric ID column and a description column. You need to select a .NET class that allows you to load the data. You also need to ensure minimal effect on the database server performance.
Which class should you use?

A.
DataSet

B.
SqlDataReader

C.
SqlDataAdapter

D.
OleDbDataAdapter