Disadvantage: Pollution to the environment by waste oil.

Disadvantage: Pollution to the environment by waste oil.

• A. Sensitivity to dirt
• B. Temperature dependence (change in viscosity)
• C. Pollution to the environment by waste oil
• D. Unfavorable efficiency factor

Answer: (C)

The key idea here is the environmental consequence of using oil-based lubricants and how waste oil creates a disposal and pollution problem. Used oil can contain contaminants and heavy metals, and if it’s not collected and handled properly, it can contaminate soil and groundwater, harm wildlife, and run afoul of environmental regulations. That makes pollution from waste oil a significant disadvantage worth addressing through proper containment, recycling, or disposal practices and spill prevention. The other points describe performance-related traits rather than disposal and environmental impact. Sensitivity to dirt affects reliability and cleanliness of the system, but it’s a maintenance/operational concern, not an environmental one. Temperature-dependent viscosity affects how the fluid behaves across temperatures, influencing efficiency and control, but it’s a fluid property, not an pollution issue. An unfavorable efficiency factor points to energy losses within the system during operation, again a performance consideration, not a disposal/pollution problem.

The key idea here is the environmental consequence of using oil-based lubricants and how waste oil creates a disposal and pollution problem. Used oil can contain contaminants and heavy metals, and if it’s not collected and handled properly, it can contaminate soil and groundwater, harm wildlife, and run afoul of environmental regulations. That makes pollution from waste oil a significant disadvantage worth addressing through proper containment, recycling, or disposal practices and spill prevention.

The other points describe performance-related traits rather than disposal and environmental impact. Sensitivity to dirt affects reliability and cleanliness of the system, but it’s a maintenance/operational concern, not an environmental one. Temperature-dependent viscosity affects how the fluid behaves across temperatures, influencing efficiency and control, but it’s a fluid property, not an pollution issue. An unfavorable efficiency factor points to energy losses within the system during operation, again a performance consideration, not a disposal/pollution problem.