Let \( L \) be a tangent to the parabola \( y^{2} = 4x - 20 \) at \( (6, 2) \). If \( L \) is also a tangent to the ellipse \( \dfrac{x^{2}}{2} + \dfrac{y^{2}}{b} = 1 \), then the value of \( b \) is equal to:
\( 16 \)
\( 11 \)
\( 14 \)
\( 20 \)