The correct options are
A Ganga and Son flowed through Magadha.
B Some parts of Magadha were forested.
C This region had iron ore.
D Elephants in forests could be trained for army.
Magadha became the most powerful mahajanapada around 600 BCE. Rivers like Ganga and Son flowed through Magadha and this resulted in ample water supplies, water transport and fertile land. Some parts of Magadha were forested and elephants in forests could be trained for army. The wood from forests could be used to make chariots. This region was also rich in iron ore which could be used to make weapons and tools.