E-waste, or E-scrap, refers to discarded electronic equipment at the end of its life. It includes devices like computers, monitors, printers, televisions, stereo systems, VCRs, and other personal electronic devices. This is exactly what the option describes, making it the best choice. The other options describe waste that isn’t electronic (non-electronic household waste, scrap metal, recyclable paper/cardboard). E-waste requires careful handling and recycling due to hazardous materials and valuable components it may contain.

Ergonomic injuries are injuries to the musculoskeletal system that come from repetitive motions, awkward postures, forceful exertions, vibration, or insufficient rest. These injuries develop over time due to cumulative stress on the body, rather than from a single acute incident. Common examples include tendinitis, carpal tunnel syndrome, and low back pain that arise from activities like repetitive typing, assembly tasks, or heavy lifting performed with poor technique. This makes the correct option the best fit because it directly describes musculoskeletal injuries caused by repetitive stress and related work factors, which is the essence of ergonomic injury in the workplace. In contrast, injuries from hazardous chemicals involve chemical exposure, those from infectious diseases involve pathogens, and injuries from electrical shocks involve electrical hazards—none of which are ergonomic in nature. Understanding this distinction helps focus prevention on proper workstation setup, tool and task design, pacing, breaks, and training to reduce repetitive strain.

Garbage is putrescible solid waste. This category covers organic materials that can decay quickly, like food scraps and kitchen waste, which readily decompose under normal environmental conditions. Because these items break down, they can cause odors, attract pests, and generate leachate, so they require more frequent collection and specific handling, such as composting or digestion. Liquid waste refers to fluids, not solids. Hazardous waste includes materials that pose health or environmental risks and need special treatment. Non-putrescible solid waste consists of dry, inert materials that don’t decompose quickly, like plastics, metals, glass, and rubble.

Limiting carbonate content in drainage material is about chemical stability over time. Carbonate minerals, like calcite or dolomite, can dissolve when exposed to leachate or groundwater whose chemistry shifts—especially if acids or CO2 build up in the pore water. When these carbonates dissolve, the solid skeleton of the drainage material weakens and the pore structure can change, which can alter flow paths, porosity, and long-term performance of the drainage layer. In short, the dissolution of carbonate minerals is a primary mechanism that can compromise drainage effectiveness and material stability over the life of the landfill. The other ideas are less central to why carbonate is limited. The concern isn’t that carbonates inherently form harmful compounds with leachate, or that they by themselves always increase water retention. Nor is the primary issue that carbonate presence directly reduces structural integrity; rather, dissolution over time is the fundamental process that motivates limiting carbonate content.