Thank you for sharing your question and situation with us.
According to the Citizenship and Immigration Canada (CIC) Call Centre, you need to include whatever documents are requested in the document checklist. If it requests your parents’ birth certificates, then you need to send them.
I know that but they what the list said. And list doesn’t say "A or B " means exactly what I have asked for. .
Anyway no problem if you don’t have answer for that .