A Statistics Instructor Wishes to Know the Average Age (In

Multiple Choice

A Statistics instructor wishes to know the average age (in month) of his 200 students.He is too lazy to sample all 200 students so he decides to choose 20 students at random from the class and ask them for their age.In the class,students are sitting in twenty rows each of size ten.He randomly selects two rows of students and samples all students in those rows.This sampling method is called a

A) Cluster Sample.
B) Simple Random Sample.
C) Voluntary Sample.
D) Stratified Random Sample.
E) Systematic Random Sample.