Which sentence uses correct punctuation with introductory phrases?

• A. The researchers proposed a revised framework after reviewing the literature.
• B. After reviewing the literature, the researchers proposed a revised framework.
• C. The researchers, after reviewing the literature, proposed a revised framework.
• D. After reviewing the literature, the researchers proposed a revised framework; this aligns with their approach.

Answer: (C)

When a phrase adds extra information about the subject but doesn’t change who is doing the action, it’s set off with commas if it sits between the subject and the verb. In this sentence, the phrase after reviewing the literature behaves as a nonessential aside about the researchers, so two commas are placed around it: The researchers, after reviewing the literature, proposed a revised framework. This punctuation makes the main point clear—who proposed the framework—while signaling the extra timing detail as optional.

This presentation is especially clean because the subject is identified first, then the extra information, then the action. (Punctuation with introductory phrases at the very start would also be correct in a different construction, but the interrupter form shown here demonstrates the comma-on-both-sides rule clearly.)

Note that using a semicolon with a following clause would require proper capitalization after the semicolon, which is why that option isn’t correct here.