explain the reason some people more than others enjoy buying a lot of
shoes.

Marginal benefit is more than marginal cost that is why some people more than others enjoy buying a lot of shoes.

Explanation:

When marginal benefit is more than marginal cost the resources were used more efficiently, when there is  increase in the quantity. Marginal cost is the cost incurred by producing one extra unit of the commodity. Marginal benefit is referred to as the extra benefit received by consuming one extra unit of the benefit.

in case of shoes the consumer will buy more shoes because he or she is getting extra benefit by consuming one extra unit but when the marginal cost becomes more than the marginal benefit he or she will not like the benefit because the consumer has to pay more for using the benefit.

the answer is a. harriet tubman was a nurse on the battlefield.

"this speech"? what speech are you talking about?