What are the three ways to measure profit margins?

What are the three ways to measure profit margins?
A . Gross profit margin = (revenue C cost of goods bought C general and administrative costs)/revenue Operating margin = EBITA (earnings after interest, taxes, and amortization)/ revenue
B. Gross profit margin = (revenue C cost of goods bought C general and administrative costs)/revenue Operating margin = EBITA (earnings before interest, taxes, and amortization)/ revenue
C. Gross profit margin = (revenue C cost of goods sold C general and administrative costs)/revenue Operating margin = EBITA (earnings before interest, taxes, and amortization)/ revenue
D. Gross profit margin = (revenue C cost of goods sold C general and administrative costs)/revenue Operating margin = EBITA (earnings after interest, taxes, and amortization)/ revenue

Answer: C