Which of the following printing initiatives would be BEST to accomplish environmentally friendly objectives?

Requiring user authentication for printing primarily addresses security and cost accounting (tracking who prints what), not necessarily environmental friendliness.

Locking down printing to only certain individuals limits access, which might indirectly reduce overall printing volume, but it's not a direct environmentally friendly setting like duplex printing.

Modifying duplex settings to double-sided printing directly reduces paper usage, which is a key environmental benefit by conserving trees and reducing waste. This simple configuration change encourages eco-friendly practices across all users.

Changing print quality settings to 'best' often uses more ink/toner and does not reduce paper consumption, making it counterproductive to environmentally friendly objectives.