business law question

SECTION 3 (CL03) (14 marks total) a) Khalid entered into a written contract to buy a limited-edition guitar (only 12 in the world) from Jack the owner, for AED 80,000 dirhams. The market price at the time of the contract is valued at AED 120,000. Jack later changed his mind and decided not to sell the guitar. Both Jack and Khalid are adults and of sound mind (not mad), and all the requirements for a valid contract were fulfilled. Advise Khalid as to the remedies/options available to him. (3 marks) b) QUIZ1 Eric gave a power of attorney to Sam which was designed to specifically authorize Sam to renew the registrations of two properties in Dubai, on behalf of Eric. Sam renovated one of the properties to make it more beautiful, and Sam also sold the other property to Barry. Both are done without Eric's authorization. However, Eric liked the renovation, but disagreed with the property being sold. Advise as to legal position regarding Eric, Sam and Barry. (Note: Explain ALL relevant legal aspects)