According to the first and second paragraphs, the brain performance peaks in late morning because a) body temperature gets higher at this time of t...

According to the first and second paragraphs, the brain performance peaks in late morning because
a) body temperature gets higher at this time of the day.
b) specific tasks stimulate the brain.
c) most people wake up quite early.
d) it’s easier to solve problems in the morning than at midday.
e) human natural rhythm reaches a steady level.