Which of the following is not the lowest term of $\frac{3}{4} \times \frac{8}{9} \times \frac{25}{40}$

Question

$\begin{array}{1 1} (a)\; \frac{10}{16} \\ (b)\; \frac{5}{4} \\ (c)\; \frac{5}{8} \\ (d)\; \frac{25}{40} \end{array}$