Choose the word which is different from the rest.

The answer is B. Pink.

Green, indigo, and violet are all primary colors of light, while pink is a secondary color. Primary colors are colors that cannot be created by mixing any other colors together. Secondary colors are colors that can be created by mixing two primary colors together.

Green is created by mixing blue and yellow light. Indigo is created by mixing blue and violet light. Violet is created by mixing red and blue light. Pink is created by mixing red and white light.

Therefore, pink is the only color that is not a primary color of light.