Let's first dissect what the survey is doing. Two questions were asked of people in an Eastern European nation about 400 famous Western brands. The first question is whether or not they recognized the brand name and the second question was whether or not they believed the product was of high quality or not.
The question stem asks which of the principles in the answer choices does the stimulus violate.
Well, what's the issue with the survey in the stimulus? The two questions are asked of all the respondents, regardless of the answer to their first question. So, even if someone doesn't recognize the brand name, they will still have to rank and rate their belief of whether or not the brand is of high quality or not.
Answer choice (A) points out this exact issue. "Never ask all respondents a question if it cannot reasonably answered by respondents who make particular response to another question in the same survey." If respondents do not recognize a brand, they cannot reasonably answer the second question of whether or not the brand is of high quality. So the stimulus is violating the principle in answer choice (A).
Hope that helped! Please let us know if you have any other questions.
