The nth element of a series is represented as

$$X_n = (-1)^nX_{n-1}$$
If $$X_0 = x$$ and $$x > 0$$, then which of the following is always true?

A

$$X_n$$ is positive if n is even

B

$$X_n$$ is positive if n is odd

C

$$X_n$$ is negative if n is even

D

None of these