Tom wants to borrow (借) your ruler, you should say "_______" [ ]

A. Sorry, I don't know.

B. Here you are.  

C. I'm OK.

D. Thank you.

螺纹上端工作塞规用于检验牙数大于4牙的内螺纹其旋合量不能多于（）。

A.3牙

B.4牙

C.1牙

D.1牙