Dave's Hobby Town and Estelle's Yarn Shoppe Are Adjacent Stores

Dave's Hobby Town and Estelle's Yarn Shoppe are adjacent stores with adjoining parking lots. Dave offers Estelle a discount on purchases from Dave's store if Estelle will not tow the cars of Dave's customers who park in Estelle's lot.
-Refer to Fact Pattern 12-1.Dave's discount is legally sufficient consideration

A) because it is a promise of something of value.
B) only if Dave adds a cash rebate.
C) only if Estelle uses it.
D) under no circumstances.