One term in the number series is wrong. Find out the wrong term. 2, 5, 10, 50, 500, 5000

The correct answer is $\boxed{\text{C}}$.

The number series is a geometric sequence with a common ratio of $5$. This means that each term is $5$ times the term before it. Therefore, the next term in the series should be $500 \times 5 = 2500$.

The number $50$ is not in the geometric sequence because it is not a multiple of $5$.