The marginal product of input 1 tells us

Select one:

a.

The change in output that results from a small change in input 2 while holding input 1 fixed.

b.

The amount input 2 must change in response to a change in input 1 in order to hold output fixed.

c.

The change in output that results from a small change in input 1 while holding input 2 fixed.

d.

The total change in output that results from changing both input 1 and input 2.