Adding Dependent child

[SAMJI]

I am adding the dependent child to CSQ. while I fill the credit card payment form, I couldn't find any suitable reason for the application to opt. Can you please help me with? Can I Leave it without selecting any option?

Link of the payment form http://www.immigration-quebec.gouv.qc.ca/publications/en/form/paiement-an-dynamique.pdf

Thanks!