Alex is working with a Normal distribution of human body weights. One of the weights in this distribution is equal to 150 pounds. When Alex converts this weight to a z-score, he obtains a z-score of 0. What does this mean?

A. Alex must have made a calculation error because a z-score can never be 0.

B. The weight of 150 pounds must be below the mean of the distribution.

C. The weight of 150 pounds must be equal to the mean of the distribution.

D. The weight of 150 pounds must be above the mean of the distribution.