— I found my mom not feeling well this morning. I’m afraid she is ill.

— _______.

A．Don’t worry too much

B．It’s nothing at all

C．I’m sorry to hear that

D．Take it easy

对于牙着色，以下哪一项可用于外源性着色的治疗（）。

A.诊室内漂白术

B.树脂修复

C.冠修复

D.无髓牙漂白术

E.超声洁牙