Which components must be guarded and maintained according to safety standards?

The correct answer emphasizes the importance of guarding and maintaining components that present significant safety risks in industrial environments. Exposed gears, belt drives, and fans are mechanical components that can cause severe injuries if workers come into contact with them while in operation. Safety standards mandate that these parts must be adequately guarded to minimize the risk of entanglement, cuts, or other types of injury.

Guarding these components involves using protective covers or barriers that prevent direct access while allowing operational functions to continue. Regular maintenance is also vital to ensure that these guards remain effective and that the equipment operates safely without exposing workers to hazards.

The other options focus on different aspects of safety but do not specifically address the most critical safety risks associated with mechanical equipment. While tools used by employees and landscaping equipment are important, they do not inherently pose the same level of risk from exposed moving parts that can be found in gears, belt drives, and fans. Therefore, while all components in a workplace should be assessed for safety, the focus on guarding and maintaining exposed mechanical components is particularly crucial in ensuring a safe working environment.