Draw individual binary relationships for each of the bullet points

- A class is taught by only one professor. No class are added without a professor. Professors can teach as many classes as theyd like; they can even take a semester off.

- An employee can write invoices, but not all employees are given this task. An invoice must have one (and only one) employees name on it.

- At a gym, a racquetball room can be reserved by a member. Members can make as many reservations as they want. Only one members name is used when reserving the room.