The house ______ roof is yellow is my grandparents'
I'm studying relative cluase of English and wondering what is the correct answer for that particular question.
At first I thought it would be
of which because then the original sentences would be:
1. The house is my grandparents' 2. Roof of the house is yellow.
But I realised that the sentence #2 lacks the proper article,
the, so I think the answer might be
However, as of my knowledge
whose is for people (or animals at best) and it is rarely used for things or objects.
So which one should be the answer? Or it is possible that the both are okay and natural? I want it to be grammatically correct but I'd also like to know which one is more 'natural'. Thanks!