Answer:
The sentence that most needs to be revised is:
A. I plan on stretching my paycheck to almost last all month.
Explanation:
We have a split infinitive in a sentence when a word (often an adverb) or a phrase is placed between "to" and the verb that form the infinitive. That is exactly what we have in sentence A. Notice how strangely broken the final part of of the sentence sounds:
I plan on stretching my paycheck to almost last all month.
The best way to revise the sentence if by simply changing the position of "almost" so that it no longer breaks the infinitive in the middle:
I plan on stretching my paycheck to last almost all month.
NOTE: Sentences B and C also have adverbs in the middle of the infinitive, but they sound much more natural and easy to understand.
