Which of the following is NOT a condition for a defendant to defend a third person's property?

The correct choice is based on the principle that a defendant's ability to use force in defense of a third person's property does not require a financial interest in that property. Traditionally, the law recognizes that certain conditions must be met for a defendant to justifiably intervene in defense of someone else's property, such as the presence of a legal duty to protect the property or a request for protection from the owner. The familial relationship and the legal duty are relevant to establishing the legitimacy of the defense, as they create a framework within which the defendant can act.

In contrast, having a financial interest in the property is not a prerequisite for a defendant to intervene in defense of another's property. This highlights that the law places more importance on the contextual circumstances rather than direct financial stakes. Thus, the concept of the justified defense of property is broad and includes various relationships but does not solely rely on the defendant having a financial connection to the property being defended.