Subject: mathqa
Question: if 45 % of a class averages 100 % on a test , 50 % of the class averages 78 % on the test , and the remainder of the class averages 65 % on the test , what is the overall class average ? ( round final answer to the nearest percent ) .
Option: 
A: 87 %
B: 86 %
C: 90 %
D: 88 %
Answer: A