【单选题】

Mrs.Cook was born in a shopkeeper’s family. Her father had several shops in the city and most of his friends are important persons. The man liked his daughter very much and often took her to the parties. He tried his best to satisfy her with everything and she wasn’t afraid of anybody.

She married Mr.Cook, a famous actor, when she was twenty-two. Her father gave her all and she does no housework at home. She often does everything she wants and makes all the family listen to her. She had a few servants, but none of them can wait on her. Neither the servants nor her husband likes her.
Last week she employed a new servant calledBetty. The girl had studied in a middle school before her father died in an accident. The girl is kind and clever. She had read a lot by then and now she knows much. She had been told about the woman before she came here. She’s sure she can deal with (对付) the woman.
The woman liked the strong and tall girl as soon as she saw her. "Remember,Betty,"said she. "You must be honest and obedient.Do you understand me!"
"Yes,Mrs.Cook, "said the girl. "But what should I do if you let me tell the visitor that you aren’t in \
Betty knows how to deal with the woman because ______ .A．She was a middle school student
B．She’s very clever
C．She knows her well
D．She had read a lot by last week