In Brindon County, virtually all of the fasteners-such as nuts, bolts, and screws-used by workshops and manufacturing firms have for several years been supplied by the Brindon Bolt Barn, a specialist wholesaler. In recent months many of Brindon County' s workshops and manufacturing firms have closed down, and no new ones have opened. Ttherefore, the Brindon Bolt Barn will undoubtedly show a sharp decline in sales volume and revenue for this year as compared to last year. The argument depends on assuming which of the following? ['The workshops and manufacturing firms that have remained open have a smaller volume of work to do this year than they did last year.', "Last year the Brindon Bolt Barn's sales volume and revenue were significantly higher than they had been the previous year.", 'The Brindon Bolt Barn is not a company that gets the great majority of its business from customers outside Brindon County.', "Soon the Brindon Bolt Barn will no longer be the only significant supplier of fasteners to Brindon County's workshops."]