A continuous time LTI system is described by
$${{{d^2}y\left( t \right)} \over {d{t^2}}} + 4{{dy\left( t \right)} \over {dt}} + 3y\left( t \right) = 2{{dx\left( t \right)} \over {dt}} + 4x\left( t \right)$$
Assuming zero initial conditions, the response y(t) of the above system for the input x(t) = e^-2tu(t) is given by

A. (e^t - e^3t)u(t)

B. (e^-t - e^-3t)u(t)

C. (e^-t + e^-3t)u(t)

D. (e^t + e^3t)u(t)

Answer: Option B