HOTSPOT
A school stores information about teachers, students, classes, and enrollments in a
Windows Azure SQL Database database. The database includes a table that maps the user
IDs of teachers to the subjects they teach.
Teachers access reports in a SQL Server Reporting Services (SSRS) instance by using their
credentials.
You are developing a report that displays a table of class enrollments for a specific subject.
The report will prompt teachers to select from their mapped subjects. The table is based on
a dataset named ClassData. To minimize report execution time, the ClassData dataset has
been configured to cache all class enrollment data.
You need to ensure that the report parameter displays the correct subjects for each teacher.
Which item should you configure? To answer, select the appropriate item in the answer
area.
Answer: 
Explanation:
As usually this Microsoft question is crappy written. You have to configure “TeacherSubjects” (datasource, duery, name of the user who executes the report as a parameter for the query, …) and then use this dataset to configure the available and default values for the parameter “Subject IMHO impossible to answer this question with the given information but I guess the answer is parameter “Subject”.
Answer should be correct. TeacherSubjects dataset is the place where teacher->subject relationship to be defined. And this could be ensured by checking the querying result of this dataset.
Actuyally, you should configure both.
The dataset should be filtered based on credentials. The parameters available values should be configured to use that dataset..