What is the nature of the following mistakes in contract common, mutual or unilateral? (9 Marks)

a. Company A agrees to sell a shipwreck to Company B. Company B spends thousands of dollars to locate the ship at certain coordinates, but the wreck did not exist to the surprise of both parties.

b. Ray agrees to sell his car to Nina. Ray was referring to his Toyota Corolla 2015 while Nina thought Ray was referring to his other car, an Audi TT.

c. Maureen is an elderly woman who could not read English and signed documents which her bank manager described was routine papers. In fact the documents included a mortgage over her house guaranteeing the debts of her grandsons business. Maureen is shocked to discover her home might be sold to pay her grandsons debts.