If R(t) Is the Position Vector of a Particle in the Plane

Multiple Choice

If r(t) is the position vector of a particle in the plane at time t, find the indicated vector.
-Find the acceleration vector. r(t) = (cos 4t) i + (5 sin t) j

A) a = (-4 cos 4t) i + (5 sin t) j
B) a = (-16 cos 4t) i + (-5 sin t) j
C) a = (-16 cos 4t) i + (-25 sin t) j
D) a = (16 cos 4t) i + (-5 sin t) j