Which of the following color combinations is most convenient during day and night?

The color combination most convenient during day and night is yellow and blue (Option C). Yellow is highly visible in daylight due to its wavelength, which stands out against natural backgrounds. Blue, on the other hand, provides good contrast in low-light conditions, such as dusk or nighttime, as it reflects well under artificial lighting and moonlight. Together, yellow and blue offer versatility in visibility across different lighting environments, making them suitable for applications like traffic signs, safety vests, and emergency vehicles. This combination takes advantage of human visual sensitivity to certain wavelengths of light, enhancing visibility and ensuring safety during both day and night. Understanding color combinations for visibility is crucial in fields such as transportation, outdoor safety, and signage design, where effective communication and recognition are essential for public safety and efficient operation.