The overriding idea in any piece of fiction is known as it's plot
B is the correct answer because it's the only one that makes sense as one sentence. The other choices you can make into two sentences.
The first one is wad snowing the next one are about to hold and the next one does not concern then protected then is given
Answer: I think A is better
"Scientists have recently been finding that microdoses of peanut butter are having a preventative effect on peanut allergies."
The present tense is better suited for the sentence as it is not future tense "will" and it is not past tense "had."