A Multiple Choice Exam Has 50 Questions with 5 Choices $\mu=10$

Multiple Choice

A multiple choice exam has 50 questions with 5 choices for each question.If an individual is simply guessing at each answer, what are the values for the mean and the standard deviation of the normal approximation to the binomial distribution for the number of correct answers?

A) $\mu=10$ and $\sigma=\sqrt{8}$
B) $\mu=25$ and $\sigma=\sqrt{8}$
C) $\mu=10$ and $\sigma=16$
D) $\mu=25$ and $\sigma=8$