Given the equation m= - 0.114c + 79.085 with r= -0.7.43, the line of best fit indicates that:

a. as the class increases by 1, the mean mark decreases by 0.114

b. as the class increases by 1, the mean mark increases by 0.114

c. as the class increases by 1, the mean mark decreases by 0.743

d. as the class increases by 1, the mean mark increases by 79.085

please and thank you.