Answer:
D ) "Even when people think they feel OK, exhaustion makes it difficult for them to learn or think as well as they can when they're rested."
Step-by-step explanation:
In her science article "The Chemistry of Sleeplessness," Emily Sohn went into detail to reveal how brain chemicals are related to how a person reacts externally. The article focuses on the issue of a brain chemical helps in keeping a person active even when he is really tired.
According to the author, she revealed that several types of research support the fact that dopamine helps a person who is tired and sleepless. It "kept the volunteers awake even though they felt tired" and also "keeps people who don't get enough sleep from conking out." But the author chooses to disagree, saying that "even when people think they feel OK, exhaustion makes it difficult for them to learn or think as well as they can when they're rested."
Thus, the correct answer is option D.