The correct option is C Green
Light is an essential factor for photosynthesis. There is a linear relationship between incident light and CO2 fixation at low light intensities. At higher light intensities, gradually the rate does not show further increase as other factors become limiting. Light between 400-700 nm wavelength constitute the photosynthetically active radiation (PAR). Maximum photosynthesis takes place in red and blue light of the visible spectrum and minimum photosynthesis takes place in the green light. The wavelength of light least effective in photosynthesis is green because plants themselves are green due to the pigment Chlorophyll.