Ed's Appliances Ltd $($Ed$\text{'}$s$)$ sold a furnace to a customer in October of $2023$ for $$10,000.$ The mark$-$up on the $$5,000$ cost of the furnace was $100\%.$ The customer paid $20\%$ of the purchase price on delivery, with the remainder of the purchase price due in March $2024.$ What is the maximum reserve Ed's can claim for the taxation year ending November $30,2023?$

$$2,000.$

$$8,000.$

$$4,000.$

$$6,000.$

None of the above.