Sarah Needs to Connect to an Interface Port on an Enterprise

Sarah needs to connect to an interface port on an enterprise switch. Her laptop does not have the correct port. When she mentions this to her boss, he tells her that they have several older laptops in a closet and one of them should have a RS-232 connector for the enterprise switch.
What does the connector that Sarah needs look like?

A) A 15 pin three row D-shaped connector
B) A rectangle with a blue connection in the middle
C) A 6 pin round connector that is purple
D) A 9 pin two row D-shaped male connector