A newsstand spends $600 a month on rent and electricity, and it spends $1.50 for each magazine that it sells. The newsstand charges $6 for each magazine. If n is the number of magazines, which equation represents the profit function of the newsstand?

A. p= 1.50n + 600
B. p= 4.50n - 600
C. p= 60-600
D. p = 600n + 4.50