Radula is a structure found in mollusks which is used for the purpose of feeding and it is often considered to be like a tongue. It has minute teeth and chitinous in nature so mainly used for scraping and cutting of the food particles.
It has been also said in the question that the new species is snail that means it belongs to the phylum mollusca. And in the organisms of the phylum mollusca, Radula serves as the rasping organ.
They all explain it, honestly, but B sounds the least like an answer they would accept as true. It's also kind of sus that they have 2 different answers about reacting differently to stress, and B is definitely the least likely of the two to be correct. Sorry I couldn't be more helpful, I'm only here because I searched for the answer myself. Good luck.
the ATP synthase complex is located in the inner membrane of mitochondria, with the ATP synthesis reaction occurring on the membrane side toward matrix compartment