Answer:b) their livelihoods are derived from the land.
Explanation: Sub- Saharan Africans are mostly dependant on the land for their actual food and to even make money to survive .
They plant and sell their food from the land to make money to buy other necessities due to the high rate of unemployment.
These are the countries that are still struggling economically to make means meet hence the countries do not provide enough employment for its people.
People are therefore dependant on the land for farming , for keeping their cattles or goats alive which they also rely on for food .
If the environment is affected that means they will be drought or other environmental issues that will demolish all these sources of living for them.
When that happens the issues of poverty and mortality then become a major problem for these countries especially infant mortality when mothers are not able to feed their infants .