Which of the following is essential for the Class C operator's training?

A Class C operator's training is essential for ensuring the safety and compliance in operations that involve underground storage tanks (USTs). Knowledge of spill response supplies is critical because Class C operators are typically the first responders in the event of a spill or leak. They need to understand the proper supplies and procedures to effectively contain and mitigate any potential environmental hazards that could arise from a fuel spill. This knowledge helps in minimizing the impact on health, safety, and the environment.

While understanding financial policies, fuel price flows, and customer service skills are important for other roles within a company, they are not directly related to the immediate responsibilities of a Class C operator, who primarily focuses on operational readiness and safety measures related to fuel storage and transfer. Thus, knowledge of spill response supplies is the most relevant and essential component of their training.