Solve the Problem $\frac { 1 } { \mathrm { x } ^ { 3 } }$

Solve the problem.
-Write the average of $\frac { 1 } { \mathrm { x } ^ { 3 } }$ and $\frac { 10 } { \mathrm { x } }$ as a simplified rational expression. (Hint: To find the average of two numbers, find their sum and divide by 2 .)

A) $\frac { 2 + 20 x ^ { 2 } } { x ^ { 3 } }$
B) $\frac { 1 + 10 x ^ { 3 } } { 2 x ^ { 4 } }$
C) $\frac { 1 + 10 x ^ { 2 } } { 2 x ^ { 3 } }$
D) $\frac { 11 } { 2 x ^ { 3 } + 2 x }$