Five colours have been given, out of which four are alike in some manner and one is different.
Select the odd one.

Green, Indigo, Pink, Orange, Yellow

Given: Green, Indigo, Pink, Orange, Yellow

Logic: The colors in the VIBGYOR spectrum (rainbow colors) are:

V - Violet
I - Indigo
B - Blue
G - Green
Y - Yellow
O - Orange
R - Red

Since Pink is not part of the VIBGYOR spectrum, while the other four colors are, Pink is the odd one out.

Thus, the correct answer is (b).