The Equation of Motion of the Wave Shown in Figure $\pi$

Multiple Choice

The equation of motion of the wave shown in Figure 13-6 is

A) y = 1.0 cos (2 $\pi$ t) .
B) y = 1.0 sin ( $\pi$ t) .
C) y = 0.5 cos (40t) .
D) y = 0.5 cos ( $\pi$ t) .
E) y = 0.5 sin (40t) .