Izzie recently took a math test where each correct answer (a) on the main part of the test was worth 7.3 points. She also correctly solved a bonus question worth 11 points. Using the equation 7.3a + 11 = 98.6, how many correct answers (a) did Izzie have on the main part of the test?
A. 15
B. 12
C. 81
D. 13
