SAT English Practice Question

A scientist is researching the use of external stimuli to reduce the itching sensation caused by an allergic histamine response. She finds that while harmless applications of vibration or warming can provide a temporary distraction, such innocuous stimuli actually offer less relief than a stimulus that seems less benign, like a mild electric shock. Which of the following is the most likely reason why the scientist uses the word "innocuous" in this context?

1. A.emphasize the temporary nature of the relief provided by vibration or warming.
2. B.highlight the contrast between stimuli that are perceived as harmless and those that seem less benign.
3. C.describe the specific effects of vibration and warming on itching sensation.
4. D.suggest that the scientist is not recommending vibration or warming as effective treatments.