The correct answer is - c. ties and connections between extended families tightened.
The development of the agriculture in early Africa, made the people to not just keep close ties with the close family members, but also with the members of the extended family.
This happened due to the organization, labor force, need for physical help. More people were managing to produce more food, more effectively, and they shared the responsibilities and labor, so people were keeping their family bonds as close as possible.