Yesterday, the price of a gallon of gas at five gas stations was $3.72, $3.87, $3.78, $4.09, and $3.989, respectively, but today each gas station raised its price by $0.08. What is today's mean price of a gallon of gas at the five stations?

A. 3.97
B. 4.05
C. 3.89
D. 3.81