In designing the features for a new auto line, an auto engineer wonders if customers have a preference between radio, CD, or MP-3 players when listening to music while driving. The engineer randomly surveys 300 customers who are shopping for a new car. Under the null hypothesis, how many customers should prefer the MP-3 player?

A.100

B.more than 150

C.close to 300

D.There is not enough information to tell.