What must be true for the use of force against trespassers on one's property?

The correct answer highlights the legal principle that any use of force against trespassers must be reasonable and necessary. This standard is fundamental in self-defense and property defense laws. Reasonableness implies that the level of force used must be proportionate to the threat posed by the trespasser. For example, if a trespasser is merely on the property without causing harm or intending to commit a crime, using excessive force in response would not be considered justified.

Additionally, necessity is a crucial component; it means that the property owner must have no other viable options, such as calling the police, before resorting to force. This principle is designed to prevent individuals from taking the law into their own hands in an arbitrary or excessively violent manner.

In contrast, the other options presented reflect conditions that might not universally apply to the use of force against trespassers. For instance, the presence of the owner, whether the trespasser is armed, or the type of property (residential or otherwise) do not solely determine the legality of the force used. Therefore, the requirement that force must be reasonable and necessary is the overarching legal standard applied in these situations.