Answer:
Part A answer: C. Sleep deprivation can cause distress in the body and mind, which makes suspects unable to understand what they are saying or the consequences of their confession.
From these options, it looks like B. supports the answer to part A the best. "When people are mentally fatigued, which is what happens in a sleep deprivation situation, they are more likely to do whatever It takes to end a punishing current situation."
Someone may confess just to get out of the situation, even if they aren't guilty. When someone is super tired, they wouldn't understand that confessing comes with consequences, that they could go to jail for the rest of their lives, they would be paying for someone else's crime.
answer: "When people are mentally and physically fatigued, which is what happens in a sleep deprivation situation, they are more likely to do whatever It takes to end a punishing current situation" (Paragraph 20)