The material lists how many types of relays?

• A. Three types: Power relays, control relays, and sensing relays
• B. Two types: Power relays and control relays
• C. Four types: Power, control, sensing, and timing relays
• D. Five types: plus auxiliary relays

Answer: (A)

Relays are categorized by their function in the system. The material identifies three kinds: power relays, which switch high-current or main circuits; control relays, used to operate control circuits and provide isolation between control logic and power circuits; and sensing relays, which monitor electrical or system conditions and trigger actions when thresholds are reached. So the material lists three types of relays. Other concepts like timing or auxiliary relays aren’t treated as separate types in this material.