我猜本题的参考答案是C where，并且我也认为应该选C，而不是A或B。

本句的关键不是定语从句修饰地点名词时如何选择关系词，而是动词leave表示离开某地或某处，在前面已经提及该地或该处的情况下，应该使用代词还是副词指代该地点或处所的问题。

例如，“他来到市场, 买了些东西，然后离开了。”这句话用英语表达时如果用leave作谓语，是不能重复名词市场的。要么leave用作不及物动词，要么用the place作宾语，要么用副词there作宾语，但较少用人称代词或指示代词指代该地点。

He came to the market, bought something and left a few minutes later.

He came to the market, bought something and left there a few minutes later.

He came to the market, bought something and left it a few minutes later.

我们读上面三个句子，会觉得前两句leave用作不及物动词或后接there作宾语读起来很自然，而用it指代market则有些不自然。

动词leave作离开解时，是可以后接副词here，there，somewhere作宾语的，尤其是口语中，并且后接人称代词it指代地点更常见。

关系词引导定语从句，其实就是关系词取代了人称代词、指示代词和指示副词。

既然地点副词可以作leave的宾语，关系副词引导定语从句时就可以作leave的宾语。it指代地点，作leave的宾语不及there自然，所以where引导定语从句并在从句中作leave的宾语，就比关系代词which或that（取代it）自然。

单选题是选择最佳答案，不是唯一正确答案，故where为最佳答案，优于用which或that。

关于leave后接地点副词作宾语证明：

1 COCA例句

 When he left there, he'd asked me to come with him to the city.

That's been circulating every year since I left there.

Reports said they initially went into the sheriff's office but later witnesses reported they left there and drove away. 

I left there for an hour and a half.

...but everybody understood we had to get a usable document by the time we left there a week after the July Fourth weekend.

 ...and there had been a few other things since I'd left there, ...

But hopefully they left there saying,' I love Coach Avalos.' 

You left there crying, did you say? 

2 BNC例句

 We left there, we left about half five, six in the morning didn't we?

We should of just got in the car and left there and then, parked 

 I was two when we left there.

But she left there and got another job in.

Well when I left there, and joined the army, I was getting twenty seven shillings a week.

Oh I cried when I left there, I really did, it upset me.

...and I think I was about fifteen when I left there.

3《朗文》注释词义时的用语

set off： （especially British English ）to leave somewhere and begin a journey

go： （especially spoken） to leave somewhere