A point moves accordingto the relation $$x = 8t^2 \cos(\omega t), y = -4t^3 \sin(\omega t)$$, where x and y are in meters, and t in seconds. If angular velocity $$\omega = 8 \pi$$ rad/sec, velocity vector of the point at t = 0.5 sec is given by

A

$$8 + j4 \pi$$

B

$$6 + j20 \pi$$

C

$$8 - j4 \pi$$

D

$$-20 \pi - j6$$