Explanation
A strategy for preventing light pollution is to install shielded fixtures. Light pollution is the excessive or inappropriate use of artificial lighting that can have adverse effects on human health, wildlife, ecosystems, and astronomy. Shielded fixtures are lighting devices that direct light downward and prevent light from escaping upward or sideways. Shielded fixtures can reduce light pollution by minimizing glare, sky glow, light trespass, and energy waste13. References: LEED v4 Green Associate Candidate Handbook1, International Dark-Sky Association's Lighting Basics3

According to the EPA and emphasized by LEED:
"The preferred waste management strategies described by the U.S. Environmental Protection Agency (EPA) are source reduction, reuse, recycling and recovery."
"Reduce" or "source reduction" is the top strategy for avoiding waste altogether.

Explanation
A neighborhood that includes a diversity of uses is most appropriate to encourage a walkable street design. A diversity of uses means that different types of activities and functions are located within walking distance of each other, such as residential, commercial, retail, educational, recreational, cultural, and civic uses. A diversity of uses creates a vibrant and lively neighborhood that attracts pedestrians and supports social interaction. A walkable street design also incorporates elements such as sidewalks, crosswalks, street trees, lighting, benches, bike lanes, public transit stops, and reduced vehicle speeds to enhance pedestrian safety and comfort. The other options are not appropriate to encourage a walkable street design. An area with a decreased building-height-to-street-width ratio creates a wide and open street that exposes pedestrians to more sun and wind, reducing their comfort level. A development that uses many culs-de-sac in the street design creates a disconnected and irregular street network that limits pedestrian access and mobility. A project in an area designed with streets to facilitate increased speed limits prioritizes vehicle movement over pedestrian safety and comfort. References: LEED Green Associate Candidate Handbook, page 29; USGBC [Location & Transportation], page 2-3.

Daylighting and natural ventilation are strategies that can be used together to save energy and improve occupant experience in a building. Daylighting uses natural light to illuminate the interior spaces of a building, reducing the need for artificial lighting and improving the visual comfort and well-being of the occupants. Natural ventilation uses outdoor air to provide freshair and cooling to a building, reducing the need for mechanical ventilation and air conditioning and improving the indoor air quality and thermal comfort of the occupants1 . References: LEED v4 Green Associate Candidate Handbook1, LEED v4 BD+C Reference Guide