Kiakaha

I definitely encountered this same question and was a bit confused. Schweser does tell you to use the averages which ends up giving you a calculation of roughly 77.56 which is close to Answer C. Knowing how to calculate the answer both ways should help. I find it unlikely that the CFAI would try to trap you on this type of question as you can see the other 2 answers are dramatically different. What they are really try to trick you on here is whether you know the difference between the operating cycle and the cash conversion cycle, where the operating cycle excludes days payable outstanding.