Retrograde amnesia is characterized by forgetting ________.

A) events that occurred in the distant past
B) events that were in the sensory register at the time of an accident
C) events preceding an accident or an injury
D) all memories related to a person's identity

Retrograde amnesia is characterized by forgetting events or information that occurred before a specific point in time, such as an accident or injury. Therefore, choice C, which states that retrograde amnesia involves forgetting events preceding an accident or injury, is the correct answer. Choices A, B, and D are incorrect because retrograde amnesia does not necessarily involve forgetting events that occurred in the distant past, events in the sensory register at the time of an accident, or all memories related to a person's identity.