# Red drop occurs in wave length of

$\begin{array}{1 1}(A)\;\text{492nm}\\(B)\;\text{535nm}\\(C)\;\text{586nm}\\(D)\;\text{680nm}\end{array}$

Wavelength of red lies between 780 to 622 nm.
Hence red drop occurs in wavelength of 680 nm.
Hence (D) is the correct answer.
edited Nov 24, 2017