Nah it wasn't, they were trying to trip you up with specifics - there's 8 bits in a byte, so a 120.6 megabyte file has 964.8 megabits, so at 16.8 megabits a second it would take 57.43 seconds, which would be C - '57' since you round down.
Similar story with the other one, there's actually 1024MB...