Mori is a famous sushi chef in Hong Kong. Takai Sushi, a sole proprietorship of Mr Takai, is a well-known Japanese restaurant in need of hiring a sushi chef. On April 28, Mr Takai posted a notice on the front door of Takai Sushi, saying "Head Sushi Chef Wanted, Annual Salary $800,000 (Negotiable), Let us know if you are interested. " On May 1, Mori saw the notice on Takao Sushi's door. He sent Takai Sushi a signed letter on the same day, stating, "I will work for Takai Sushi as a head sushi chef for two years for an annual salary of $1,000,000." On May 7, Mr Takai posted a letter to Mori which stated "The $1,000,000 is pretty high. Could you possibly consider working for less"? On May 9, Mori replied Mr Takai's letter and stated "I am a world-famous sushi chef. I will not work for any less." Upon receiving Mori's reply on May 10, Mr Takai immediately posted Mori a signed letter stating that "Okay, if you really won't work for less, I agree to pay you the $1,000,000 a year you demand to work as head sushi chef at Takai Sushi for two years." At 9:00am on May 11, while Mr Takai's letter was still being delivered, Mori accepted an offer to work for another restaurant Hayashi House. At 12:00 noon, Mr Takai's letter was delivered to and received by Mori. Mori called Mr Takai and said, "Sorry, I just took a job at Hayashi House. Too bad you cannot afford me." Mr Takai responded, "You cannot work for Hayashi House, I already accepted your offer to work for Takai Sushi for $1,000,000 a year." Required: (a) Explain whether the display of the notice on the front door of Takai Sushi with the annual package mentioned is an offer or invitation to treat. You are required to cite a relevant case to support your answer. (13 marks) (b) Considering the rules of offer and acceptance, advise whether Mori is legally bound to work for Takai Sushi. You are required to cite a relevant case to support your answer. (11 marks) (c) Explain whether valid consideration exists in the transaction between Mori and Takai Sushi to constitute a legally binding contract. (6 marks)