Which crop is commonly rotated with rice in Assam?

The correct answer is (d) Mustard.

Mustard is a common crop that is rotated with rice in Assam. It is a winter crop that is planted in October or November and harvested in March or April. Mustard is a nitrogen-fixing crop, which means that it helps to improve the soil’s nitrogen content. This is beneficial for rice, which is a nitrogen-hungry crop. Mustard is also a good source of oil, which can be used for cooking or making biodiesel.

Potato (a) is a tuber crop that is not commonly rotated with rice in Assam. Sugarcane (b) is a perennial crop that is not commonly rotated with rice in Assam. Tea (c) is an evergreen shrub that is not commonly rotated with rice in Assam.