One of the main problems that prevents africans from working together is:
feudalism
communism
apartheid
tribalism

Tribalism

Explanation:

The problem of Africa is not necessarily tribalism but rather it the problem is the diversity in culture. However, since tribalism is the closest option in the question; then tribalism, it is.

Africa is a continent with a wide range and varieties of tribes. The number of tribes in Africa,is estimated to be about 3,000 tribes, speaking more than 2,000 different languages.

This diversity of African communities poses a difficulty in integrating them to work together. This is so because language barrier and illiteracy are central to this problem.

Generally, African countries are highly diverse in view of some of the exclusive primordial markers, particularly ethnicity and most countries use different languages other than English. Network user interfaces to these languages are unavailable and developments in transliteration are in very early stages.

c, they united with once

d) the lindbergh baby kidnapping

hope this