c
(c)
Equation of travelling wave
$y=a \sin 2 \pi\left(p t-\frac{x}{5}\right)$
Maximum particle velocity $\left(v_y\right)=A \omega$ or $v_y=a \times 2 \pi p$
Wave velocity $(v)=\frac{\omega}{k}=\frac{2 \pi p}{2 \pi / 5}=5 p$
$\therefore \frac{v_y}{v}=\frac{2 \pi a}{5}$