Which one of the following is NOT a real option?

a. The option to abandon a project if cash flows turn out to be lower than expected.

b. The option to switch the type of fuel used in an industrial furnace to lower the cost of production.

c. The option to expand into a new geographic region.

d. The option to buy shares of stock if its price is expected to increase.

e. The option to expand production if the product is successful.