Which of the following is an example of a valid offer?

Group of answer choices

Tim advertises in a newspaper to sell his car for $$4,000.$

A tire manufacturer sends his quotation to a car manufacturer for a particular make of tire at $$50.$

Walmart advertises that all canned juices in its stores would be available at a discount of $50$ percent on the printed price.

A laptop showroom advertises that every laptop purchased would be eligible for a free backpack, subject to availability.

A backyard sale at Castle estate advertising the sale of all items in an auction for up to $50$ percent discount.