You'll need to figure out how much of your net profit would be included in your Arkansas return. You can do this by apportioning part of your net profit to Arkansas. Since Arkansas uses a sales-only factor, your apportionment factor is calculated as:
Arkansas Sales/Everywhere Sales
For example, if your total sales for the year were $50,000 and $10,000 of those sales were from Arkansas sources, your apportionment factor would be $10,000/$50,000 = 20%.
Then you'd take that 20% and multiply it by your net profit to figure out how much you should include in that box.