How Might a Marketing Manager for a Manufacturer of Turboprop

How might a marketing manager for a manufacturer of turboprop engines used in private jet planes use the North American Industry Classification System (NAICS) to help with his marketing planning to find prospective customers?

A) He could record the NAICS numbers for each of his firm's best customers, and then obtain lists of companies with the same NAICS numbers.
B) He could go to a library to find the NAICS numbers for all government units, federal, state, and local.
C) He could identify all NAICS numbers that do not reflect the classifications of his firm's customers.
D) He could poll his field sales organization to see if his company's sales representatives know what NAICS numbers mean.