Serena is an editor who uses a team of grammar proofers on original drafts. The price that she charges a publishing company for a proofing assignment can be expressed as 500+25ph, where p is the number of proofers she uses and h is the number of hours the assignment will take to complete. Which of the following is the best interpretation of the term 500 in the expression? A. Serena charges $500 per proofer for a proofing assignment.
B. Serena charges a flat fee of $500 per assignment in addition to the hourly fee that she charges for the proofing.
C. Serena charges a maximum of $500 for the hourly fee per assignment.
D. The product of the number of proofers times the number of hours needed to complete the assignment is 20.