How is an arrest defined?

An arrest is defined as restricting a person's movement against their will, which is precisely what the correct answer articulates. This definition captures the essence of an arrest, as it involves the law enforcement authority's power to take someone into custody. The key aspect is that the individual does not consent to this action, highlighting that an arrest is inherently an exercise of authority rather than a voluntary act by the individual.

While the other options touch on aspects related to law enforcement or intervention, they do not encapsulate the fundamental nature of what constitutes an arrest. For instance, detaining a person after consent does not qualify as an arrest since it lacks the coercive element that characterizes the act of arresting. Incarceration refers specifically to the act of placing someone in jail or prison for a crime, which usually follows an arrest but is not synonymous with it. Issuing a warning lacks any implication of custody or restriction of movement, which is crucial in defining an arrest. Thus, the correct option provides an accurate and comprehensive understanding of what an arrest entails.