Continental Shelving Company made a sale to Excalibur Knives for $5,000 on December 10, 2020. Approaching year-end, Continental wanted to encourage prompt payment, so it provided generous discounts for those clients able to pay promptly. The invoices state the payment terms to be 3/10 net 45. Excalibur pays the invoice on January 20, 2021. 

Required:

How should Continental record the invoice and its subsequent collection if the company uses.

(a) The gross method. 

(b) The net method.