Solve the Initial Value Problem Using an Integrating Factor $y ^ { \prime }$

Multiple Choice

Solve the initial value problem using an integrating factor.
- $y ^ { \prime }$ + y = 3; y(0) = 0.

A) y = $e ^ { - t }$ (3t - $e ^ { - t }$ )
B) y = $\sqrt { 6 t }$
C) y = 3 - 3 $e ^ { - t }$
D) y = 3t