The mountains in the north of the Indian subcontinent hindered, but did not prevent, foreign invasions. Which statement BEST explains why foreign invasions of ancient India succeeded? A.
Japanese invaders were forced to attack India by sea.

B.
Invaders from southeast Asia could come through the foothills and the Ganges River Valley.

C.
The mountains were not high enough to be a real deterrent.

D.
Invaders were able to reach India through passes in the western section of the mountains.