In a statistics course, a linear regression equation was computed to predict the final exam score from the score on the first test. the equation was y=10+0.9x where y is the final exam score and x is the score on the first test. Bill scored a 90 on the first test and his residual was -2. what was his score on the final exam?

a. 89
b. 91
c. 93
d. 90
e. not enough information