I have a question related to my Economics Homework, I need a fully detailed explanation, not just the answer. Please give me a logical step-by-step

breakdown, because I am having a hard time understanding this problem below - Many Thanks.

Refer to the following table:

Level of Activity Total Benefit Total Cost Net Benefit Marginal Benefit Marginal Cost

0 ______ 0 0 xx xx

1 100 50 _____ ______ ______

2 ______ ______ 100 150 ______

3 ______ ______ 115 _____ 160

4 605 ______ _____ _____ 179

5 ______ 674 _____ 120 _____

6 825 ______ _____ _____ 190

The optimal level of activity is:

A. 2

B. 3

C. 4

D. 5

E. There is no optimal level in this case because marginal benefit does not equal marginal cost at any activity level.