In each of the following sentences, there is a blank space. Below each such sentence, there are five options with one word each. Fill up the blank with the word that makes the sentence grammatically and contextually correct.
Access to a closely guarded military plan would mark a sharp expansion of Mr. Musk's role as the Trump adviser who is ___________efforts to cut U.S. government spending.

The word "spearheading" means leading or directing an effort, which makes sense in this context where Mr. Musk is involved in efforts to cut government spending. The other options are incorrect:"Upstaring" isn't a word in this context."Complying" means following or adhering to something, which doesn’t fit here."Procuring" means obtaining or acquiring, which doesn’t fit the idea of leading an effort."Clucking" refers to the sound a chicken makes, and is clearly irrelevant to the sentence.Therefore, "spearheading" is the correct choice.