$4\mathrm{.}1$ Represent each of the following sentences by a Boolean equation.

$($a$)$ The company safe should be unlocked only when Mr$.$ Jones is in the office or Mr$.$ Evans is in the office, and only when the company is open for business, and only when the security guard is present.

$($b$)$ You should wear your overshoes if you are outside in a heavy rain and you are wearing your new suede shoes, or if your mother tells you to$.$

$($c$)$ You should laugh at a joke if it is funny, it is in good taste, and it is not offensive to others, or if it is told in class by your professor $($regardless of whether it is funny and in good taste$)$ and it is not offensive to others.

$($d$)$ The elevator door should open if the elevator is stopped, it is level with the floor, and the timer has not expired, or if the elevator is stopped, it is level with the floor, and a button is pressed.