Using legal authorities, explain whether Donald is required by the law of contract to fulfil his promises in ALL the following situations:

(a) Donald promises to sell his Ferrari to George in return for 2 and a banana; AND

(b) Donald returns home to find that his house windows have been cleaned by Jimmy and he then promises to pay Jimmy 30 for his work; AND

(c) Donald agrees to pay Richard 600 for painting his shed white, to be finished within 3 weeks. He later promises a further 50 if Richard finishes the job on time; AND

(d) Donald promises to release Hillary from a debt of 5000 if Hillary gives him 400; AND (e) Donald promises to release Hillary from a debt of 5000 if Hillary gives him $400 and an iPad.