Question

Can someone please help me .

An obstacle that prevents many Americans from exercising is _____.

the lack of an exercise partner
living too close to a park
the lack of need to exercise
a lack of understanding about the importance of fitness

Answer 1

D the lack of understanding the importance of fitness

Answer 2

An obstacle that prevents many Americans from exercising is a lack of understanding about the importance of fitness.
It's not that they don't need to exercise - they certainly do, but they don't understand why that is necessary.
I don't see how living too close to a park prevents anybody from exercising. And exercising is a good way to find an exercise partner, so A is also incorrect.