A、When she was only ten. B、When she was only fourteen. C、When her brother was only ten. D、When she went to university. A听出材料的第二句

I had a working mother when I was a young girl. She went back to work when I was ten and my brother was fourteen. She taught at a school of dress design. I studied English at university. Then I got a job with an advertising agency as an assistant. I studied English so I could get a good job with a good company. In 1980 I went abroad with a friend. We spent a month in California Then I worked for a company which sold cassette tapes and books for English conversation. I was still single at 25 . then my parents started to worry because their daughter wasn’t married.
   Our neighbors and relations were asking when I would marry and they began to talk about an arranged marriage. In Japan they don’t force you to marry someone, but they may give you a chance to meet someone. I am very interested in jazz and I met my husband in a jazz club. My parents didn’t want their daughter to marry a foreigner. They didn’t want me to come to England. but now I work in London for a Japenese newspaper.
When did her mother go back to work?