选A.
在限制性定语从句中,当先行词指人时,关系词可用who(m)或that,二者常可互换.
但在下列情况中,用who(m),而不用that：
(1) 当先行词是one,ones,any,few,anyone,anybody,someone,somebody,everyone,
everybody等词时.如：
Is there anyone who can answer this question?
He was among the few who managed to live through the enemy prison camp.
注：在非正式文体中可以说：You’re the one that knows where to go.)
(2) 当先行词是he,they,those,people,person等词时.如：
He who wants to catch fish just not mind getting wet.
Those who are against the proposal put up your hands.
注：在固定结构的谚语或习语中,可用he that….如：
He that promises too much means nothing.
(3) 当先行词有较长的后置定语修饰时.如：
Do you know the writer in blue with thick glasses who is speaking at the meeting?
(4) 在分隔式定语从句中,若先行词指人,为了明确修饰关系,应当用who(m).如：
A new master will came tomorrow who will teach you German.
There’s only one student in the school who/whom I wanted to see.
I was the only person in my office who was invited.
(5) 两个定语从句同时修饰一个指人的先行词,第二个定语从句常用who(m)来引导,如：
She is the only girl I know who can play the guitar.
此题属于第二种情况.
