If $f: R \rightarrow R$ and $g: R \rightarrow R$ are two functions defined by $f(x) = ax + b$ $(a \neq 0)$ for all $x \in R$ and $g(x) = cx^3 + d$ $(c \neq 0)$ for all $x \in R$,then $(f \circ g)^{-1}(x) =$

• A
  $\left( \frac{x - ad + b}{ac} \right)^{\frac{1}{2}}$
• B
  $\left( \frac{x + ad - b}{ac} \right)^{\frac{1}{3}}$
• C
  $\left( \frac{x - ad - b}{ac} \right)^{\frac{1}{3}}$
• D
  $\left( \frac{x + ad + b}{ac} \right)^{\frac{1}{3}}$