Buying drinks at a bar

A blonde, a brunette and a redhead went into a bar and ordered their drinks from the bartender.Brunette: "I'll have a B and C." Bartender:"What is a B and C?" .Brunette: "Bourbon and Coke." Redhead: "And, I'll have a G and T." Bartender: "What's a G and T?" Redhead: "Gin and tonic." Blonde: "I'll have a 15." Bartender: "What's a 15?" Blonde: "7 and 7"