The steeper an isoquant is (labor measured on the horizontal axis): A. the greater is the level of output. B. the greater is the need to keep capital and labor in fixed proportions. C. the greater is the marginal productivity of labor relative to that of capital. D. the greater is the substitutability between capital and labor.

C

Explanation:

A graphical representation that shows contour lines which are drawn through the same point sets at which the output level is constant and the level of two or more inputs are changed.

Now, for a production isoquant with a steeper slope, we can see that there is a greater marginal productivity of Labour relative to that of capital.

Simply because labour has been more productive, more capital is needed for less labor and this causes the curve to be steeper.

b is the correct answer