Einstein's voice against nuclear weapons clarifies which ethical limit of science?

Correct answer: The need to protect scientific knowledge from destructive use

The governing concept is ethical responsibility in the application of knowledge. Scientific discovery can increase human power, but the use of that power is shaped by social choices and moral judgement. Einstein’s opposition to nuclear weapons highlights the danger that scientific understanding may be directed towards mass destruction rather than human welfare. Option A is correct because it recognises the need for safeguards, public responsibility and humane purposes; it does not reject science itself. Option B is wrong because knowledge does not automatically guarantee ethical action. Option C reverses the moral lesson by presenting weapons as the highest purpose of knowledge. Option D is also false, since concern for human life is precisely what makes the issue ethical. The episode expands the scientist’s role from discovering facts to considering consequences.