Which of the following would best satisfy the requirements for a good legal offer?

Select one:

a."I'll drive you to Seattle on Saturday."

b.On a flyer placed on your windshield):"We have the best offer in town! A mint 1956 Chevrolet for $20,000."

c."The purchaser will pay $1000 for one of the seller's laser printers, the exact model to be determined at a later date."

d."I'll pay you at least $300 for your horse, Blackie, and even more if the horse is lucky."

e."I'll give you $1 for your new green bike."