What is white light? Contrast the design and efficiency of the incandescent lamp with the fluorescent lamp. 
a) White light is a combination of all visible wavelengths. Fluorescent lamps are more efficient but have a slower start-up time compared to incandescent lamps. 
b) White light is produced by fluorescent lamps only. Incandescent lamps have a simpler design but are less energy-efficient than fluorescent lamps. 
c) White light consists of a single wavelength. Fluorescent lamps have a higher energy consumption compared to incandescent lamps. 
d) White light is produced by incandescent lamps only. Fluorescent lamps have a shorter lifespan but are more environmentally friendly.