Use the Following Information for Questions

Multiple Choice

Use the following information for questions:
Olivia wants to learn a foreign language. To get an idea of how satisfied other students were after taking a foreign language course, she decides to take a random sample of 20 students.
-If Olivia randomly selects one class among all the foreign language classes taught that year, and then interviews all students in that class, the sampling method is a

A) simple random sample.
B) stratified random sample.
C) cluster sample.
D) systematic sample.