A person is justified in the use of force to defend himself or another against another's imminent use of _____ force.

The justification for a person to use force in self-defense or in defense of another is rooted in the notion that one can protect themselves against an imminent threat. When referring specifically to "unlawful" force, it highlights that the use of force must respond to actions by another person that are not authorized by law. This means if an individual is faced with an unlawful threat—such as an attack or aggression that breaches the law—they have the right to use reasonable and proportional force to defend themselves or another person.

In the context of self-defense laws, "unlawful force" indicates that the assailant is acting outside their legal rights, making it permissible for the victim of that aggression to respond. The focus is on the legality and the nature of the force being used against them, affirming their right to protect themselves.

While the other options might refer to types of force, only "unlawful" clearly encompasses the threshold that justifies a defensive action. Therefore, recognizing the nature of the force involved is critical to understanding the legal ground for self-defense.