题目内容：

    It's believed that people reach their mental peak (顶峰) in their 20s. However, this isn’t completely true. According to a recent study by scientists from the Massachusetts Institute of Technology in the US, people are best at doing different things at different ages. They studied many people aged 10 to 90 years old, who were asked to take part in different memory tests.

1.At what age can people reach the peak of their attention?

A.2. B.18. C.45. D.50.

2.Which fact does the passage provide?

A.The younger people are, the better memory they have.

B.The study is based on some research on people of all ages.

C.People in their 40s can understand others' feelings best.

D.Different people are good at different things at the same age.

3.This passage is probably a(n) ________________.

A.novel B.report C.advertisement D.notice