Find the difference between the largest 5 digit number and smallest five digit number by the digits 9, 3, 7, 1, 8 and multiply the result with 5?

Question

$\begin{array}{11} (a)\;424710 \\ (b)\; 4567865 \\ (c)\; 6965447 \\ (d)\; 1116200 \end{array}$