Which of the following Indian states share border with multiple countries?
a) Manipur b) Mizoram c) Tripura d) Bihar e) Sikkim f) West Bengal g) Assam

Manipur shares its border only with Myanmar. 
Tripura shares its border only with Bangladesh.
Bihar shares its border only with Nepal.

Sikkim shares its border with Nepal, Bhutan, and China. 
Mizoram shares their border with both Bangladesh and Myanmar. 
Assam shares its border with both Bangladesh and Bhutan. 
West Bengal shares its border with Nepal, Bhutan, and Bangladesh. 

Therefore, option B is the right answer.