A $2.0 \mathrm{~kg}$ Mass Is Moving in a Circular Path with a Radius

A $2.0 \mathrm{~kg}$ mass is moving in a circular path with a radius of $5.00 \mathrm{~cm}$ . The mass starts from rest and, with constant angular acceleration, obtains an angular velocity of $6.00 \mathrm{rad} / \mathrm{sec}$ in $3.00 \mathrm{sec}$ . The mass then comes to a stop with constant angular acceleration in $4.00 \mathrm{sec}$ . The radial component of acceleration of the mass at $5.00 \mathrm{sec}$ after the start is

A) $2.50 \mathrm{~m} / \mathrm{s}^{2}$ .
B) $0.980 \mathrm{~m} / \mathrm{s}^{2}$ .
C) $0.450 \mathrm{~m} / \mathrm{s}^{2}$ .
D) $1.25 \mathrm{~m} / \mathrm{s}^{2}$ .
E) $2.03 \mathrm{~m} / \mathrm{s}^{2}$ .