The solution of the equation $$y'' + y = 0$$ satisfy the condition $$y(0) = 1, y\left(\frac{\pi}{2}\right) = 2$$, is

A

$$\cos x + 2 \sin x$$

B

$$\cos x + \sin x$$

C

$$2 \cos x + \sin x$$

D

$$2(\cos x + 2 \sin x)$$