Izzie recently took a math test where each correct answer (a) on the main part of the test was worth 7.9 points. She also correctly solved a bonus question worth 15 points. Using the equation
7.9a+15=101.9, how many correct answers (a) did Izzie have on the main part of the test?
a. 15
b. 7
c. 11
d. 12