Which of the Following Is an Offer as Opposed to an Invitation

Multiple Choice

Which of the following is an offer as opposed to an invitation to treat?

A) An ad in a real-estate paper: "Best offer in Vancouver! 3-bedroom home in Kitsilano for only $850,000!"
B) A sweater displayed in the window of a shop with the price tag attached and showing.
C) A notice in the Toronto Star: "I will pay $100 to whoever finds and returns my lost female calico cat which answers to the name Marx."
D) The display of goods on the shelves of Costco.
E) A notice in the catalogue from the gift shop of the Edmonton Aquarium: "15% off the price of all jewellery until January."