The tree___shade you are standing was planted
by an old man.
A whose B in whose C in its D which
此题选B，为什么？请诸位帮忙解释并且翻译。谢谢浏览者和回答者。O(∩_∩)O

1)whose指代The tree，in whose shade，在树荫里。you are standing 是the tree的定语从句。

我认为你不容易理解是因为whose在定语从句中通常做主语等。在这里的成分是在介词短语状语中。

本句也可以写作：
The tree whose shade you are standing in was planted
by an old man.
这样，whose shade 引导定语从句you are standing in


2）翻译：你站在树荫里的那棵树是一位老人种植的。

3）whose[关系代词]那个人的, 他[她]的, 他们[她们]的; 它(们)的
可以代人或者物。
He is the man whose house was burned down.
他就那个房子被烧毁的人。（主语）
This is the pen whose point is broken.
这就是笔尖断了的那枝笔。（主语）
This is the cat in whose left ear there is a hole.
这就是那个左耳上有个洞的猫。（介词短语，状语）