Astudent offering instructor $$20$ to grade their work is an example of$...$

My boss told me "You're doing a great job. I$\text{'}$m going to give you $200$ shares of company stock" Claiming a contract exists will fail because this is an example of$...$

Getting the wrong address, Joes Painting accidentally painted my house as I watched through the window but didn't stop the painters. Joe's sends me a bill. On what basis would I have to pay the bill.

I moved to Chicago to start a new job I was hired for. Upon arrival $|$ am told the job no longer exists. I will have to be compensated under the legal of$...$

You and I agree that I will give you $$5$ and $1,000$ lemon drop candies for your iphone. You want to rescind the contract but will lose. This is an example of$...$