Select the meaning of the word 'reflex' in the sentence: 'The typical patellar reflex takes only 50 milliseconds between the initial tap and the leg extension.'
Correct Answer: C
Rationale: In the context of the sentence, the word 'reflex' indicates a quick, automatic response by the body to a stimulus. The patellar reflex, also known as the knee-jerk reflex, involves the leg extending in response to a tap on the patellar tendon. Therefore, the word 'reaction' aligns closely with the nature of the patellar reflex in terms of a rapid and involuntary response. Choices A, B, and D are incorrect: 'Replication' does not capture the concept of a bodily response, 'convulsion' implies a sudden and uncontrollable movement which is not specific to the nature of the patellar reflex, and 'stretching' does not encompass the automatic and rapid nature of a reflex action.