I think the cost of capital or sales in year one because it will have the biggest negative impact on the NPV.

Sensitivity Analysis
Parameter	Initial Assumption	Worst Case	Best Case
Sales in Year 1	$30,000	$27,000	$33,000
NPV	$ 4,225	$ (124)	$ 8,574
Sales Growth through Year 6	6%	0%	10%
NPV	$ 4,225	$ (853)	$ 8,200
Cost of Goods Sold (% of Sales)	72%	77%	67%
NPV	$ 4,225	$ (2,460)	$ 10,911
Cost of Capital	20%	23%	17%
NPV	$ 4,225	$ 1,294	$ 8,360
Question: Suppose you are the financial manager, if you are asked to use limited resources to refine the assumption on ONLY ONE of the above four parameters, which one should you choose and why? (fill in the blanks highlighted in yellow)