An online store sells two types of T-shirts: basic T-shirts and premium T-shirts. Each basic T-shirt costs $8, and each premium T-shirt costs $15. The equation represents the total revenue in dollars, where is the number of basic T-shirts sold and is the number of premium T-shirts sold. In this equation, what does the coefficient 15 represent?
The total number of T-shirts sold.
The cost of one basic T-shirt.
The total revenue from basic T-shirts.
The cost of one premium T-shirt.
