In Terms of Price Variability and Marketing Strategy, Variable Pricing

In terms of price variability and marketing strategy, variable pricing is a strategy

A) that allows a firm to set prices based on negotiations with the customer or based on customer buying power
B) that is aimed at consumers who are averse to negotiations but who want, nevertheless, to have some sort of low price guarantee
C) whereby a firm sets prices and attempts to maintain them over time
D) of changing prices in response to changes in demand or cost