Let \( f(x) = x^5 + 2x^3 + 3x + 1, \ x \in \mathbb{R} \), and \( g(x) \) be a function such that \( g(f(x)) = x \) for all \( x \in \mathbb{R} \). Then \( \dfrac{g(7)}{g'(7)} \) is equal to:
\( 42 \)
\( 7 \)
\( 14 \)
\( 1 \)