Who is Bill's favorite writer?
1. It is Arthur Conan Doyle.
2. He is Arthur Conan Doyle.
3. Arthur Conan Doyle is.
4. Arthur Conan Doyle is his favorite writer.
5. Arthur Conan Doyle is his favorite.
(Which expressions are grammatical and commonly used?)
They're all grammatically correct.
From my experience, I'd have to rank them in order of preference: 1 3 5 4 2
Good job, Steve!
The grammatically correct and commonly used expressions in this context are:
1. It is Arthur Conan Doyle.
4. Arthur Conan Doyle is his favorite writer.
5. Arthur Conan Doyle is his favorite.
These options clearly state that Bill's favorite writer is Arthur Conan Doyle.