If the Revenue Function Is $R ( x ) = x ^ { 2 / 3 } + 2 x ^ { 1 / 2 } + 6 x + 2$

Multiple Choice

If the revenue function is $R ( x ) = x ^ { 2 / 3 } + 2 x ^ { 1 / 2 } + 6 x + 2$ for producing a product, find the marginal revenue at a production level of 10 units.

A) $\frac { 2 } { 3 }$ $( 10 ) ^ { - 1 / 3 }$ + $( 10 ) ^ { - 1 / 2 }$ + 6
B) $\frac { 2 } { 3 }$ $( 10 ) ^ { - 1 / 3 }$ + $4 ( 10 ) ^ { - 1 / 2 }$ + 6
C) $( 10 ) ^ { 2 / 3 }$ + 2 $\text { (10) } 1 / 2$ + 6(10) + 2
D) $\frac { 2 } { 3 }$ $( 10 ) ^ { - 1 / 3 }$ + $( 10 ) ^ { 1 / 2 }$ + 6
E) $\frac { 2 } { 3 }$ $( 10 ) ^ { 1 / 3 }$ + $( 10 ) ^ { 1 / 2 }$ + 6