B. If I won the lottery, I'd buy a big house.
I'd say probably when the person you are contacting prefers communicating via call or text or another form of messaging. For almost anything professional or business related, it would be appropriate and acceptable to email.
Answer:
They are below.
Explanation:
1) who's
2) who
3) who
4) which
5) who
6) that
I hope this helps you. :)
