To clarify, did you parents claim you as a dependent on their tax return last year and this year you will be filing your own return? Additionally, if you are filing your own return, will your parents be claiming you as a dependent on their tax return?
If your parent's are not claiming you as a dependent for the 2021 Tax Year, then you will say "No", since it is your parent's who received your stimulus payment and not you. This way you will be able to get the stimulus payment added to your refund.
