Context: The model below represents a molecule of trichlorofluoromethane. Trichlorofluoromethane was once used in refrigerators and fire extinguishers. It is no longer used because it harms the atmosphere's ozone layer.
Complete the statement.
Trichlorofluoromethane is ().
A. a compound
B. an elementary substance
Identify the correct choice from the options below and respond with the letter of the correct option.

A