Which one of the following would not shift the demand curve for US domestic airline travel in January?

a. An increase in the cost of automobile gas which consequently makes driving long distances more expensive than before. b. An increase in the cost of jet fuel. c. An earthquake in California which leaves many tourist attractions closed. d. A cold spell in Florida. Note: Florida is typically warm in January and so attracts tourists for that reason.

e. A mild winter in the northeastern US so there is less desire to escape south.