Sodium vapor lamps are often used for street lighting because

Sodium vapor lamps are often used for street lighting because their light is monochromatic and does not disintegrate when passing through water drops (option B). These lamps emit light primarily at a specific wavelength corresponding to sodium atoms’ characteristic yellow color. This monochromatic nature minimizes color distortion and ensures consistent visibility, even in adverse weather conditions where other types of streetlights might scatter or disperse light, reducing visibility. Additionally, sodium vapor lamps are energy-efficient and have a long lifespan, contributing to cost savings and environmental sustainability. While they provide bright illumination (option D) suitable for street lighting, their specific advantage lies in maintaining visibility and reducing glare and light pollution, enhancing safety for drivers and pedestrians alike. Their cool operation (option C) also contributes to their suitability for urban environments. Therefore, sodium vapor lamps are favored for street lighting due to their monochromatic light that maintains visibility in various weather conditions, improving overall safety and efficiency in city lighting.