Fill in the blanks. When choosing the levels of two activities, A and B, in order to maximize

total benefits within a given budget:

a. If at the given levels of A and B, MB/P of A is ...... MB/P of B, increasing A and decreasing B while holding expenditure constant will increase total benefits.

b. If at the given levels of A and B, MB/P of A is .......... MB/P of B, increasing B and decreasing A while holding expenditure constant will increase total benefits.

c. The optimal levels of A and B are the levels at which ............. equals ...........