In order to encourage bowel health, older people are advised to choose foods that are naturally rich in______.

A．Because he thought the job was boring.
B．Because his health got poor.
C．Because he wanted to enjoy his life with his family.
D．Because he wanted to realize his dreams of life after retirement.

A．At a laboratory.
B．At a bank.
C．In a classroom.
D．In a department store.