Mr. Gupta decides to score the tests by giving 10 points for each correct question. He also plans to give every student 5 additional bonus points. Let y represent a random student's score. What are the mean and standard deviation of y?

a) Mean: 15, Standard Deviation: 10
b) Mean: 10, Standard Deviation: 5
c) Mean: 20, Standard Deviation: 5
d) Mean: 15, Standard Deviation: 5