4. A bank vault has 3 locks with a key for each lock. Key A is owned by the bank manager. Key B is owned by the senior bank teller. Key C is owned by the trainee bank teller. In order to open the vault door at least two people must insert their keys into the assigned locks at the same time. The trainee bank teller) can only open the vault when the bank manager is present in the opening. X= Bank Manager Y= Senior Bank teller Z= Trainee bank teller. (25 marks) LO 01 a) Construct a truth table for this system