The distance between cities A and B is 120 miles.  A car travels from ... ...

The distance between cities A and B is 120 miles.  A car travels from A to B at 60 miles per hour and returns from B to A along the same route at 40 miles per hour.  What is the average speed for the round trip?
(A) 48
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Nova Press: Set H - Elimination Strategies