[单选题]
A wave travels on a vmqi+ij,0 ie;5xh 7rfchix0 3ropei 7vc.3 ts kdms x,xxts2yt9+. as shown, where $P$ is a point on the rope halfway between the equilibrium position and the maximum displacement.
Which is correct about the direction and magnitude of the velocity of point $P$ after half a period compared to the shown position?
A. Direction Up;Magnitude Increases
B. Direction Up;Magnitude Same
C. Direction down;Magnitude Decrease
D. Direction down;Magnitude Same
