A principal wants to know if students at a particular high school are in favor of a new dress code at their school. The principal is not able to ask the opinion of every student at the school, so she needs to select an appropriate sample of the students to represent the high school.
Select which sample of students the principal should choose.

A
Students randomly selected from a list of all students at the school.
B
Students sitting at randomly selected tables in the library.
C
Students she selects from the hallway between classes.
D
Students selected by the teachers.