What are the four requirements of a valid contract? What are the defenses to the enforceability of a contract? Did Duncan have a valid contract with Mitsui for employment as CDO? If so, was it a...

What are the four requirements of a valid contract?

What are the defenses to the enforceability of a contract?

Did Duncan have a valid contract with Mitsui for employment as CDO? If so, was it a bilateral or unilateral contract?                                          What are the requirements of an implied contract?

Can Duncan establish an implied contract based on the employment / or the written compensation plan? Why or why not?