From where ? Can you give some background information as to what you want answered
A complex sentence contains one independent clause and at least one dependent clause. Here, in your example, there are two simple independent clauses which you need to merge using a dependent adjectival clause in order to make one complex sentence. Here is how to do it:
The boy <u>who wore a green coat</u><u /> carried his sister home.
Your answer is C..
if this answer is incorrect, then i am sorry..
