explain why is the particular answer

During a meeting with a department clerk, the clerk's supervisor learns that the clerk is being harassed by a buyer. The department already has a publicized anti-sexual harassment policy, and has implemented a procedure for employees to follow if they feel they have been the victim of sexual harassment. Which of the following is the BEST course of action for the supervisor to take? A. Instruct the clerk to report the harassment in writing B. Conduct a department-wide sexual harassment prevention training program C. Ask the clerk to confront the buyer, to try to resolve the issue D. Take immediate and appropriate corrective action to end the harassment