The owner of Darkest Tans Unlimited in a local mall is forecasting this month's (October's) demand for the one new tanning booth based on the following historical data:What is the monthly rate of change (slope) of the least squares trend line for these data?Month #VisitsApril 100May 140June 110July 150Aug 120Sept 160a. 320b. 102c. 8d. -.4e. -8