The table compares the average daily temperature and ice cream sales each day.

Temperature (°F) Ice Cream Sales
56.1 $107
60.3 $116
64.2 $120
66.4 $122
71.3 $125
73.9 $130
74.2 $132
75.2 $135
80.1 $141
84.8 $152


What is the slope of the line of best fit, where x represents the average daily temperature and y represents the total ice cream sales? (Round your answer to one decimal place.)

a. 6.3
b. 4.2
c. 2.8
d. 1.4