A. subtle because they're basically making an analogy. For example, some people like cats, while others like dogs. In this case, some people like subtle flavors, while others like spicy hot flavors. Also, none of the other words make sense in the sentence because vivid is usually used to describe colors, universal is used to describe something people do all around the world, and delusional means that you are having thoughts or visions that contradict reality. So, A. subtle is the answer.
Answer:
laboratory observation
Explanation:
According to my research on different research methods, I can say that based on the information provided within the question the most appropriate method of study in this situation would be a laboratory observation. This is because this method is the most efficient method, mainly because it would allow for special equipment to measure the physiological changes. Another good method would have been a naturalistic observation, but since the Professor wants to measure psychological changes and not observable changes this will not suffice.
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Im pretty sure its the first option