17. Ben works at a mobile phone store, where he earns a flat $80 for each 8-hour shift. He also earns a commission of $20 for each phone that he sells. If e stands for Ben's earnings and m is the number of mobile phones he sells, which of the following equations describes the amount of money that he earns in one shift? A) e = m + 100
B) e = 20m + 80
C) e = –20m + 80
D) e = m + 80