C is the answer for this question
Because he was against slavery and the southerners knew that he would put a law on slaves and it would cause the southerners to Lose money
Imperialism was all about the control of goods in the market at that time. Of course, entailed in the market transactions are the exchange of human resources. The Christian missionaries played a role in the emergence of slave trade that was happening in East Africa in their aim to free the slaves on the basis of human rights violation.