Which of the following best defines "physical injury"?

The definition of "physical injury" encompasses a broad range of bodily harm, and the most comprehensive understanding of this term includes conditions that lead to significant impairments or alterations in bodily function. Therefore, the option referring to death or impairment of any body part effectively captures the full scope of physical injuries, which can range from minor to severe consequences.

This understanding aligns with legal and medical definitions where physical injury is viewed in terms of the impact on an individual’s physical state, capabilities, or well-being. Significant impairments can involve various degrees of injury, including those leading to permanent disability or death.

The other choices do not fully encapsulate the broader implications of physical injury. Minor bruising is limited in scope and does not reflect the seriousness that the term can entail. Temporary psychological distress, while it may affect an individual's well-being, does not represent a direct physical injury to the body. Similarly, injuries related to aging, while they may affect physical capabilities, do not distinctly address the concept of injury as it applies in a more legal or medical context. Thus, option B accurately describes the serious nature of physical injury.