The disturbance $$y(x, t)$$ of a wave propagating in the positive $$x$$-direction is given by $$y = \frac{1}{1+x^2}$$ at time $$t = 0$$ and by $$y = \frac{1}{[1+(x-1)^2]}$$ at $$t = 2$$ s, where $$x$$ and $$y$$ are in meters. The shape of the wave disturbance does not change during the propagation. The velocity of wave in m/s is

A

2.0

B

4.0

C

0.5

D

1.0