There are a couple differences between (B) and (C) which make (B) the stronger answer choice.
First, even ignoring the S&N aspects of both principles, answer choice (B) more closely aligns with Mary's decision. We do not know whether Mary is against experimenting on animals in general. We only know that she is against experimenting on animals where the animal will neither regain consciousness nor survive the experiment.
Second, the principle outlined in answer choice (C) is more radical than the principle outlined in answer choice (B).
Answer choice (C) suggests that Mary would only ever experiment on animals if future animal suffering were prevented.
FASP --> JEA Not JEA --> Not FASP
There is no evidence presented in the passage to suggest that (a) future animal suffering will not be prevented by this experiment and (b) Mary would only ever experiment on an animal for this reason.
On the other hand, answer choice (B) directly aligns with Mary's decision.
J --> IA Not IA --> Not J
This principle suggests that Mary would not be justified in taking the life of an animal if it would neither immediately help save the lives of several animals nor immediately protect the health of a person. The key word here is "immediately." As this is just a lab experiment examining the physiological consequences of shock, there is no evidence to suggest that either of these outcomes will occur; therefore, Mary is not justified in taking the dog's life.
Overall, answer choice (B) is a better answer choice because it is a more specific and less radical principle which more closely aligns with Mary's decision.
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