Choose the correct option:

Options

A. Light of single wavelength is called monochromatic light.
B. The best monochromatic light are LASERs in which the spread of wavelength is very small but not zero.
C. The wavelength of visible light is around 380-780 nm. The obstacles or openings encountered in normal situations are generally of the order of mm. As wavelength is several is thousands times smaller than the usual obstacles or openings. The diffraction (bending of light) is almost neglible and light waves propagate in straight lines and cast shadows of obstacles. This is the geometrical optics approximation. By the above analysis rectilinear propagation of light can be explained.
D. All options are correct.

Answer

D