Answer:
A. Sentence 2: Change "were gone" to "had simply vanished"
Step-by-step explanation:
By changing the sentence (2) "Most of the bees were gone" into "Most of the bees had simply vanished", we will get a more definite reason for the disappearance of the bees. Using "had gone" is just not too much emphasis on the occurrence and the gravity of the situation, while "had simply vanished' would have more stronger sentence hold on the reader.