The Laplace Transform of x(t) formed by convolution operator is:

$$x(t) = \left\{t.u(t)\right\}\otimes \left\{\cos 2 \pi t.u(t)\right\}$$

A

$$\frac{1}{[s(s^{2} + 4 \pi^{2})]}$$

B

$$\frac{1}{[s^{2}(s^{2}+4 \pi^{2})]}$$

C

$$\frac{2 \pi}{[s(s^{2}+4 \pi^{2})]}$$

D

$$\frac{s^{3}}{[(s^{2}+4 \pi^{2})]}$$