Which safety systems are commonly found in excavators?

Excavators are heavy machinery that involve significant risk during operation, which is why safety systems are critical. The correct choice emphasizes the importance of alarms, emergency stops, and rollover protective structures. Alarms are essential for warning operators and nearby personnel of potential hazards, while emergency stops allow for quick cessation of operation in case of an emergency, minimizing the risk of accidents or injury. Rollover protective structures (ROPS) are crucial for protecting the operator in the event of a rollover, which is a specific hazard associated with the height and weight distribution of excavators.

The other options, while they may include features pertinent to machinery, do not address the primary safety concerns specific to excavators. Fuel efficiency indicators and speed regulators can enhance operational efficiency but do not directly contribute to the safety of operators and workers. GPS tracking and remote operation controls focus more on efficiency and operational management rather than immediate safety features for the operator. Automatic lubrication systems and air conditioning improve maintenance and comfort during operation but are not safety systems. Thus, the correct answer reflects the safety features that ensure operator protection and hazard awareness on excavators.