The control operator that is manually actuated by the operator prior to and during the arming and firing of the effect.

• A. Enable
• B. Fire
• C. Fail-safe
• D. Enable button

Answer: (D)

The key idea is a deliberate, operator-initiated control that grants permission to arm and fire. The enable button exactly fits this role: it must be pressed by the operator before arming and kept engaged during the arming and firing process. This provides a safety step to prevent accidental activation and ensures the sequence only proceeds with intentional input. The actual firing is typically triggered by a separate fire control after enabling, while a fail-safe is a safety mechanism designed to prevent unsafe operation rather than a manual step used during arming.