The correct answer is: A. Hopefully
The sentence is grammatically correct, but the word “hopefully” is not necessary. It can be removed without changing the meaning of the sentence.
The word “hopefully” is an adverb that means “in a hopeful manner.” It is often used to express a wish or expectation. In this sentence, the word “hopefully” is used to express the writer’s hope that the building will be completed before the rainy season sets in. However, the meaning of the sentence is clear without the word “hopefully.” The sentence could be rewritten as “We will be able to complete the building before the rainy season sets in.”
The word “hopefully” is sometimes considered to be a filler word, or a word that does not add any meaning to a sentence. It can also be seen as a sign of uncertainty or lack of confidence. In this case, the writer is expressing a confident expectation that the building will be completed on time. Therefore, the word “hopefully” is not necessary and can be removed without changing the meaning of the sentence.