Diamond Company has three product lines, A, B, and C. The following financial information is available:

Item	Product Line A	Product Line B	Product Line C
Sales	$30,000	$45,000	$12,000
Variable costs	$18,000	$24,000	$7,500
Contribution margin	$12,000	$21,000	$4,500
Fixed costs:
Avoidable	$4,500	$9,000	$3,000
Unavoidable	$3,000	$4,500	$2,000
Operating income	$4,500	$7,500	($500)

Assuming that Product Line C is discontinued and the manufacturing space formerly devoted to this line is rented for $6,000 per year, operating income for the company will likely:

Increase by $7,200.

Increase by $3,300.

Increase by some other amount.

Be unchangedthe two effects cancel each other out.

Increase by $4,500.

Can you show how you got the increases in bold above in excel?