$$\text { Find the value of } ( f \circ g ) ^ { \prime } \text { at the given value of } x \text {. }$$

Multiple Choice

$$\text { Find the value of } ( f \circ g ) ^ { \prime } \text { at the given value of } x \text {. }$$
- $$f ( u ) = \frac { 1 } { u } + 19 , u = g ( x ) = \frac { 1 } { x ^ { 2 } - 19 } , x = 10$$

A) 10
B) 20
C) -39
D) 100