The University of Vancouver Offers Summer Courses from May to August.Students

The University of Vancouver offers summer courses from May to August.Students must register and pay in March for the summer courses they will take.The university has a March 31st fiscal year-end and does not recognize the revenue from the summer courses until the new fiscal year.Which revenue recognition criterion prevents them from recognizing the revenue in March?

A) The collectability of the amount is uncertain.
B) The amount of revenue cannot be reasonably measured.
C) The costs required to earn the revenue cannot be reasonably measured.
D) The university has not done most or all of what it has to do in order to earn the revenue.