Answer:
credit card
Explanation:
In the case of a recurring payment such as is needed in this scenario, the best payment option is a credit card. Credit Cards will allow the payment to go through automatically without the need for manual approval. This also applies regardless of your current bank balance. The payment will go through on the first day of each of the 15 years as long as the credit card is still active and you can pay the credit card bill when it arrives. That way it will not matter if you forget about paying it exactly on the first day of the year.
