Let a casual $\text{LTI}$ system be governed by the following differential equation $y\left ( t \right ) + \dfrac{1}{4}\dfrac{dy}{dt} = 2x\left ( t \right )$, where $x(t)$ and $y(t)$ are the input ant output respectively. Its impulse response is

1. $2e^{-\frac{1}{4}t}u\left ( t \right )$
2. $2e^{-4t}u\left ( t \right )$
3. $8e^{-\frac{1}{4}t}u\left ( t \right )$
4. $8e^{-4t}u\left ( t \right )$