Which of the Following Is True with Regard to Price

Which of the following is true with regard to price?

A) Historically, price has had the least perceptible impact on buyer choice.
B) Price is the least flexible element in the marketing mix.
C) Unike product features and channel commitments, prices cannot be changed quickly.
D) Price is the sum of all the values that customers give up to gain the benefits of having a product.
E) Prices only have an indirect impact on a firm's bottom line.