If the position vector of an object is r(t)=2t2i^4tj^ , what are the instanteneous velocity vector components at t=2s ? Select one: a. vx = 4 m / s vy = 3 m / s b. vx = 8 m / s vy = 4 m / s c. vx = 4 m / s vy = 0 m / s d. vx = 2 m / s, vy = 4 m / s