If the constant term in the expansion of \( \left(\dfrac{\sqrt[5]{3}}{x}+\dfrac{2x}{\sqrt[3]{5}}\right)^{12} , \; x\neq 0 \), is \(\alpha \times 2^{8} \times \sqrt[5]{3} \), then \( 25 \alpha \) is equal to:
\( 693 \)
\( 724 \)
\( 742 \)
\( 639 \)