Which of the following is a symptom of a spinal cord injury?

A symptom of a spinal cord injury is the loss of movement or sensation below the level of the injury. This occurs because the spinal cord serves as the main pathway for information traveling between the brain and the body. When the spinal cord is damaged, the signals that control movement and sensation can be interrupted, leading to paralysis or loss of feeling in parts of the body that are innervated by nerves below the injury site. The specific outcomes depend on the location and severity of the injury; for example, higher-level injuries can lead to more extensive loss of function.

The other choices, while potentially related to various medical conditions, do not directly reflect typical symptoms of a spinal cord injury. A headache may occur for numerous reasons, increased heart rate is more often associated with systemic responses to stress or injury, and nausea can arise from a variety of factors unrelated to spinal cord injuries specifically. Thus, the most directly relevant symptom of a spinal cord injury is the loss of movement or sensation below the site of damage.