A real estate firm has three offices. Which of the following statements BEST describes its obligation to display the firm's license certificate(s)?

A. The license certificate must be prominently displayed at the main office only.

B. The license certificate must be displayed at the main office with copies posted at each branch.

C. The license certificate must be displayed at the main office with the license of the supervising broker displayed at each branch office.

D. A license certificate must be obtained for and displayed at each office.