Ross Times, the student newspaper of Ross College, printed a "What do you think?" column feature discussing the parking situation on campus. To gather student opinion on parking, an editor for the paper stood at the entrance to the student union and gathered responses from students as they left. In all, 126 responses were collected.
This is an example of:
A a convenience sample.
B a simple random sample.
C a multistage sample.
D a cluster sample.
E a voluntary response sample.