If the coefficient of \( x^{7} \) in \( \left(ax-\dfrac{1}{bx^{2}}\right)^{13} \) and the coefficient of \( x^{-5} \) in \( \left(ax+\dfrac{1}{bx^{2}}\right)^{13} \) are equal, then \( a^{4}b^{4} \) is equal to:
\( 44 \)
\( 33 \)
\( 22 \)
\( 11 \)