We identify a user's answer by number (1,2,3 or 4) or option text.
If users comment only numbers without text then there is a chance that FB will consider their comments as spam and won't post it. Usually, it happens if you have more than 6 game rounds. So we highly recommend encouraging your users to comment number + text instead of just a number.
Let check an example:
Let say the correct answer is number 1 "Arm".
Here are acceptable options of comment:
"arm i guess"
"i'm sure it is aRm"
Not acceptable options of comment:
As you see we ignore letter case and can use just a number or a just text to identify the answer.