Father Christmas Is a Retail Store in Winnipeg That Sells

Father Christmas is a retail store in Winnipeg that sells one-of-a-kind Santas made from fur, wool, and tapestry. The store has 5 cash registers and a total "operating liability ratio" of 100. If 150 customers wish to buy Santas from this store, and it sells only 120 before running out of stock, what is its service level?

A) 80 percent
B) 125 percent
C) 150 percent
D) 66.7 percent
E) 20 percent