Class Attendance Today Is Nearly 100%,but on Most Other Days

Multiple Choice

Class attendance today is nearly 100%,but on most other days it is less.The likely explanation for this would be

A) the opportunity cost of not attending today is much higher than usual.
B) random chance.
C) everything on TV was a rerun.
D) students thought today's class was a review.
E) the opportunity cost of attending today is much higher than usual.