Single-throw knife switches shall be installed so that gravity will tend to close the switch.
See answer and applicable Code reference
The correct answer is: b) False
You can find the Code requirements for switches in Art. 404. The rules for the position and connection of switches are outlined in Sec. 404.6. As per 404.6(A), "Single-throw knife switches shall be placed so that gravity will not tend to close them. Single-throw knife switches, approved for use in the inverted position, shall be provided with an integral mechanical means that ensures that the blades remain in the open position when so set."