What does the 'I' in PIES stand for?

• A. Igniter
• B. Impulse
• C. Initiator
• D. Instrument

Answer: (C)

Initiator is the element that triggers the sequence or system. In the PIES mnemonic, the I represents the initiating action or device that starts the procedure by sending the initiating signal to the system. This fits best because the emphasis is on what starts the process, not on something that creates energy (igniter) or a measuring/control device (instrument). An igniter would imply combustion, which isn’t how these procedures are started; an impulse is a brief energy burst, not a defined component; an instrument is just a device for measurement or control, not the trigger itself.