Correct Answer: D
Explanation:
A careful reading of the sentence suggests that the missing word is related to slowing down of the heart as the sentence clearly brings out that the pulse rates drop. Therefore, A, D and E could be the likely answers. However, we need to choose only two words that mean the same and which will impart the same meaning to the sentence when placed in the blank. Therefore, D and E are the correct answers as out of these three words, ‘choke’ and ‘throttle’ are the closest in meaning.