The ignition method that uses an electric spark to ignite the pilot is called the

• A. Intermittent pilot
• B. Standing pilot
• C. Hot surface ignition
• D. Electronic ignition

Answer: (A)

The main concept here is how a furnace lights gas using different ignition schemes. The phrase describes a system where a spark is used specifically to light a small pilot flame, and then that pilot flame lights the main burner when heat is needed. That setup is known as intermittent pilot ignition. It lights the pilot only when there's a call for heat, saving gas compared to keeping a pilot flame burning continuously.

Standing pilot keeps the pilot flame on all the time, which isn’t about sparking to light the pilot each cycle. Hot surface ignition uses a glowing element to ignite the gas directly without a pilot flame. Electronic ignition refers to electronic control of ignition, which often lights the burner directly with a spark or sometimes uses other means, not necessarily lighting a pilot flame on every cycle. So the option described—the spark lighting the pilot—fits intermittent pilot ignition.