Total cost and number of units in the first seven months of 2020 are given below. According to this information, which of the following is the cost equation? Periods Total No.of Units Cost 45,750 500 January February 510 46,305 March 520 46,860 April 545 48,248 May 565 June July 49,358 50,190 51,855 580 610 Select one: O a. Y=18000+55.5*X O b.Y=21000+50*X O c. Y=22500+48.3*X O d. Y=19000+52.5*X