Which component is responsible for triggering the mortar round's ignition?

The component that initiates the ignition of a mortar round is the fuse. The fuse is a crucial part of the mortar round's design, as it is responsible for controlling the timing of the detonation. When the mortar round is fired, the fuse activates and ensures that the ignition occurs at the appropriate moment during flight or upon impact. This activation is key to ensuring that the round explodes only when intended, optimizing its effectiveness against the target.

While other components like the detonator, primer, and ignition cord play essential roles in the overall functioning of munitions, they operate in conjunction with the fuse for the ignition process. The detonator often initiates detonation and is triggered by the fuse, while the primer typically serves to ignite the propellant charge within ammunition. The ignition cord, on the other hand, is designed for specific types of detonations and is not typically involved in the ignition of mortar rounds directly. Therefore, the fuse's role in timing and determining when the mortar round ignites is critical, making it the correct answer.