When white light passes through rain drops it undergoes dispersion to form a rainbow. Then 
a) In the case of primary rainbow light entering the water drop undergoes one reflection and two refractions 
b) In the case of a secondary rainbow, red colour will be at the bottom and violet colour at the top
c) In the case of secondary rainbow, light entering the water drop undergoes two reflection and two refractions
d) In the case of primary rainbow, violet colour will be at the top and red at the bottom 
Chose the correct option