Final answer:
The narrator's opinion on preserving the corpse seems to lean towards finding the practice disturbing (Option B), especially in the context of Thessalian corpse guarding involving supernatural threats, although there is an element of passive acceptance in other contexts.
Step-by-step explanation:
The narrator's perspective on preserving the corpse varies across different passages. In the first passage, the narrator does not overtly oppose the idea of preserving Madeline's corpse due to the specific circumstances provided by her brother—the unusual malady and inquiries by doctors—though he finds it a bit unsettling. This suggests a reluctant acceptance or at least a passive stance (Option C) towards the decision, as it was viewed as a harmless precaution.
In the context of the second passage, preservation of the corpse is not directly mentioned, but there is an indication of resigned acceptance to circumstances due to fatigue, possibly hinting (though not explicitly) at a general ambivalence or lack of opinion (Option C) from another character.
The third passage delves into the practice of vigilant corpse guarding in Thessaly, which the narrator does find disturbing due to the supernatural implications and the risks involved. This indicates towards a more negative perspective (Option B), finding such actions disturbing when considering the danger and moral implications.