Final answer:
a) Decreased pain tolerance. Decreased pain tolerance is a normal age-related change that increases an elderly patient's risk for accidental injury.
Step-by-step explanation:
The normal age-related change that increases an elderly patient's risk for accidental injury is decreased pain tolerance. As people age, they may experience a decrease in pain perception, which can make them less aware of injuries or conditions that require medical attention. This can result in delayed treatment and increased vulnerability to accidental injuries. For example, an elderly person may not feel the pain from a fall or a burn and may not seek immediate medical help.