Final answer:
The shipper cannot use the provided UPS account number as the payment method code 120412 for shipping.
Step-by-step explanation:
In the context of shipping, a shipper refers to the person or company that is sending the goods. The UPS account number is often used as a payment method when shipping through UPS. However, in this case, the shipper cannot use the provided UPS account number as the payment method code 120412. This may be due to various reasons such as the account being inactive, having insufficient funds, or the shipper using a different payment method for this particular shipment.