The quote from the text that best supports the answer to Part A is option B: "the so-called reward systems in their brains are very sensitive while circuits involved in self-control are still not fully developed" (Paragraph 5).
This quote supports the idea that the teenage brain is more prone to risky behavior because the reward systems in their brains are highly responsive, while the circuits responsible for self-control are not yet fully developed. Essentially, this means that teenagers may be more likely to engage in risky behaviors because they are driven by the immediate rewards they experience, without fully considering the potential consequences.
The quote highlights the imbalance between the reward systems and self-control mechanisms in the teenage brain, which contributes to their increased susceptibility to engage in risky behaviors. It suggests that the sensitivity of their reward systems outweighs their ability to exercise self-control, leading to impulsive decision-making.
By citing this quote, it becomes evident that the teenage brain's reward systems and self-control circuits play a crucial role in shaping their behavior and decision-making processes.