What does the random variable for a binomial experiment of n

What does the random variable for a binomial experiment of n trials measure? PICK ONE OF THE FOLLOWING.

A. The random variable measures the number of failures out of n trials.

B. The random variable measures the standard deviation of n trials.     

C. The random variable measures the number of successes out of n trials.

Solution

C. The random variable measures the number of successes out of n trials.