In the Ideas Sector Production Function $\Delta A _ { t } = \bar { z } A _ { t } ^ { 1 / 2 } L _ { a t }$

In the ideas sector production function, $\Delta A _ { t } = \bar { z } A _ { t } ^ { 1 / 2 } L _ { a t }$ , there are:

A) increasing returns to the ideas stock but decreasing returns overall
B) decreasing returns to the ideas stock but increasing returns overall
C) decreasing returns to the ideas stock and labor
D) increasing returns to the ideas stock and labor
E) None of these answers are correct.