A school librarian wants to increase the number of students who read in their tree time. He survey aimed at finding out what kinds of reading material would make students at his school most
likely to read in their free time.
Which random sample would give the librarian the most useful results?
A) 20 students in a history class
B) 100 students who participate in after-school sports
C) 20 students at the school library
D) 100 students in the cafeteria during lunch time.