Which of the following is NOT an example of valid consideration in the contract law context? Group of answer choices-Samuel really likes Brett's sunglasses and offers to purchase them from Brett for $100. Brett purchased the sunglasses a day earlier for just $15, but he accepts Samuel's offer to purchase them for $100.-Jeff Bezos enters into a contract to purchase a condo on Fifth Avenue in New York City that is next to his own condo so that he can knock out the walls and increase the size of his condo. The contract provides that Bezos will pay $16 million for the condo, even though the same condo sold for about $11 million a few years ago and has not been changed since then.-RoofCo enters into a valid contract to install a new roof on Doug's house for $5,000. The roofing materials only cost about $500, so the contract price mostly consists of labor expenses. When the roofing job is half finished, RoofCo asks Doug for an additional $1,500 to complete the job exactly as previously promised by RoofCo, with no changes at all to RoofCo's obligations. Doug agrees to modify the contract and pay the additional amount.-Richard promises to give his grandson $500 if the grandson (who is 22 years old and in college) refrains from drinking alcohol and smoking for one year