Which of the following sentences is correct?

Correct answer: He was completely exhausted, yet he continued studying for his exam. “Yet” correctly joins the two contrasting ideas.

Background: “Yet” means “but” and shows contrast.

• He was completely exhausted, yet he continued studying for his exam!: The exclamation mark does not suit the sentence.
• He was completely exhausted, when he continued studying for his exam: “When” does not show contrast.
• None of these: “None of these” is incorrect because the third sentence is correct.

Did you know? Other contrast words are “but” and “however”.

Memory trick: Contrast → yet.