A. The payment process request pays only $200 USD alone.

B. The payment process request doesn't select the invoice or credit memo for payment because the credit reduces the payment to - $25 USD, which is below zero.

C. The payment process request applies $200 USD of the credit memo to the invoice, leaving a remaining credit of $25 USD, and creates a payment for $0 USD.

D. The payment process request creates a refund for $225 USD and leaves the invoice unpaid.