The equation of a simple harmonic wave is

given by

where x and y are in meters and t is in

seconds. The ratio of maximum particle

velocity to the wave velocity is

(a) $2\mathrm{\pi }$

(b) $\frac{3}{2}\mathrm{\pi }$

(c) $3\mathrm{\pi }$

(d) $\frac{2}{3}\mathrm{\pi }$