Hello, why is the answer not: "ridicule of scientists who were members of the English upper class and who were thought to demean themselves by engaging in the manual labor required by their experiments."

The line in question tells us that despite the clamor, many scientists actually farmed off some of their work to paid technicians. This indicates that the clamor in question was contrary to the reality of farming off work to servants. This is further supported in the first paragraph, where we are told that the self-image of a scientist of that era was that they performed their experiments themselves. This is a great match for D. However, this directly undermines B. The passage tells us that the scientists in question actually bucked this trend, and were generally supportive of doing their own manual labor.