<u>Option-(D):</u> Everyone who is headed to Disney World this weekend needs to pack their bags as tightly and lightly as possible.
Explanation:
Grammar is more precise and more demanding when it comes to the arrangements of the different words inside a paragraph or a sentence in order to provide the full sense to all the readers or just the audiences. While, there are some sentences or we can just say that there are certain rules and principles on which the different ideas are written and pronounced. Same is the case for the case for this sentence,as the pronouns-antecedent agreement requires the singular nouns to have the position replaced by the singular form of pronouns inside a paragraph or any sentence. So, we can just say, that as "the pack" and the "tightly and lightly" requires a proper way to describe the whole situation for the sentence or paragraph.