If the temperature outside is 86°F, the heat index can be found using the equation y = 0.004x2 − 0.1243x + 84.028. This equation is also the curve of best fit for the values in the table. In the equation, x represents the relative humidity and y represents the heat index. Relative Humidity Heat Index 40% 85°F 55% 89°F 75% 97°F 90% 105°F 100% 112°F Using the curve of best fit, if the current temperature is 86°F and the relative humidity is 55%, what is the heat index? Round the answer to the nearest degree. A. 78°F B. 88°F C. 89°F D. 90°F