Correct Answer: Green light

Solution : The correct option is Green light

Green light is the least efficient in photosynthesis. Plants generally utilise red and blue light for photosynthesis because chlorophyll, the pigment responsible for collecting light energy, absorbs these wavelengths more efficiently. Since chlorophyll reflects and transmits green light, it is less effective at stimulating photosynthesis. Because plants reflect green light while absorbing other colours for energy, they look green to human eyes. While green light does help to photosynthesis to some level, its overall efficacy is lower than that of red and blue light.