Contract law

Here is the case:

Bob paints cars in his commercial paint booth in his auto paint business, Bobs custom Auto Paints, but he does not have a current business license or approval from the Regional Air Quality Control District. Jim the owner of a custom car detailer next door asks Bob, Can you paint my 1965 Mustang this week? I want to give it to my son for his college graduation next Wednesday. Ill be out of town until next Tuesday, how does $1500 sound? Bob says to Jim, I guess that would be OK but I have to check some other stuff. Just leave it in the driveway I suppose. Jim parks the car in Bobs driveway with a check for $1500 on the drivers seat and leaves town for the rest of the week. The two business owners do not speak again until Jim returns on Tuesday afternoon to find the Mustang sitting in Bobs driveway unpainted and the check not cashed. Jim is very angry and is threatening to file a lawsuit to force Bob to immediately paint the car and recover as much damages as possible, including punitive damages. Since you work in the legal claims department, Bob is requesting you prepare a report forhis review on the following questions:

Is there a valid and enforceable contract? Explain why.

Do all of the required elements exist? Explain facts from the case to demonstrate that they exists

What possible defenses to the formation of a contract might Bob have?

Your response must be based on the facts as presented in the case.