XYZ Ltd's income statement for accounting purposes for its year ended December 31, 2021 shows a profit of $180,000 from the sale of widgets to a valued customer. The gross proceeds were $300,000 and the cost of sales was $120,000. The gross proceeds of $300,000 are payable in four equal instalments of $75,000, due on June 1 each year, commencing June 1, 2021. The deduction necessary to reconcile accounting income to income for tax purposes for 2021 in respect of this transaction is:

		Nil
		$135,000
		$144,000
		$45,000