Consider the signal \[X\left( t \right) = \left\{ \begin{gathered} 2\cos \left( t \right) + \cos \left( {2t} \right);\,\,\,t < 0 \hfill \\ 2\sin \left( t \right) + \sin \left( {2t} \right);\,\,\,t \leqslant 0 \hfill \\ \end{gathered} \right.\]
The signal X(t) is

A. periodic with period 2π

B. periodic with period π

C. non-periodic

D. periodic with period $$\frac{\pi }{2}$$

Answer: Option C