The universal product code $($UPC$)$ is a

a$.$ series of numbers that uniquely identifies a company's product line after obtaining a trademark.

b$.$ series of thick and thin vertical lines read by computerized optical scanners that match codes with brand names, package sizes, and prices.

c$.$ name that identifies a product by class or type and therefore cannot be trademarked.

d$.$ name, term, symbol, design, or combination thereof that identifies a seller's products and differentiates them from competitors' products.