这个题考查定语从句
先把句子分开一下：
The boss had heard about the accident .
Mr King worked in the boss' department.
可见 翻译如下：
那个老板听说了事故,李明就在这个老板所在的部门.
in the boss' department= in whose department
whose指代先行词boss 在定语从句中做定语
而在这个定语从句in whose department Mr King worked中
in whose department 又充当worked的地点状语