I don't understand how the answer of (B, 2) was calculated

I don't understand how the answer of (B, 2) was calculated in Practice Exam 2, question #11: Here is the question: 1. Suppose that in a particular sample, the mean is 50 and the standard deviation is 1. What is the Z score associated with a raw score of 101? What was the math process used to calculate it? 

1