问题详情

According to this passage, it is normal that ______.
A．a 1-year-old cannot recall what has happened one month ago
B．a 20-year-old can recall what happened when he was 2
C．a 20-year-old fails to recall what has happened one month ago
D．a 40-year-old has few memories for an event that happened 20 years ago请帮忙给出正确答案和分析，谢谢！