The most suitable sentence correction for the underlined part will be:
<h3>What is sentence correction?</h3>
Sentence correction is a type of grammatical practice where a sentence is given with a word or a phrase that requires grammatical changes or improvement.
Now,
In the given sentence, "While these classes are particularly helpful to young students developing basic research skills, <u>but</u> adult patrons can also benefit from librarian assistance in that they can acquire job-relevant computer skills",
The most appropriate sentence correction for the underlined part would be: DELETE the underlined portion and end the sentence with a period (option D).