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

a.

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

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 drive you to Seattle on Saturday."

e.

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