答案是 C of which
This morning是状语
I是主语
called是谓语
a travel agent是宾语 后面是定语从句
其中 of which 是带介词的关系代词 引导定语从句 并作从句中的定语
相当于介词短语作定语
the telephone number 是定从中的宾语
I是定从中的主语 got 是定从中的谓语
from one of my good friends .是定从中的状语
of which the telephone number
=whose telephone number
=telephone number of which它引导的是哪个从句啊，具体在从句中做什么成分？谢谢！已经回答
of which the telephone number
=whose telephone number
=thetelephone number of which