Context: Bangladesh faces continuous challenges from river erosion that reshape its landscape, displace communities, and affect agriculture, infrastructure, and local economies. Consider the social, environmental, and policy dimensions of river erosion when responding to the sub-questions below.

a. Write a composition of about 200 words on "River Erosion in Bangladesh".

b. List and briefly explain four major natural and human causes of river erosion in Bangladesh.

c. Describe three specific impacts of river erosion on agriculture and rural livelihoods.

d. Suggest four practical measures (short- and long-term) to reduce river erosion and help affected communities adapt.