找出下列各个句子中有错误的一项，将其序号填在前面的括号里。
--How much is your pen? --__________
A. It's black. B. Eight. C. 30 yuan.
--How many books do you have? --________
A. I have ten. B. I can see ten. C. I have a new book.
--what's his name? ______________.
A. Her name is Sarah. B. His name is John. C. He's thin.
We have six new ___________.
A. light B. fans C. pen
The ball is ___________.
A. in the door B. in the bed C. under the chair