Indiscriminate disposal of used fluorescent electric lamps causes mercury pollution in the environment. Why is mercury used in the manufacture of these lamps?

• A. A mercury coating on the inside of the lamp makes the light bright white.
• B. When the lamp is switched on,the mercury in the lamp causes the emission of ultra -violet radiations.
• C. When the lamp is switched on,it is the mercury which converts the ultra-violet energy into visible light.
• D. None of the statement given above is correct about the use of mercury in the manufacture of fluorescent lamps.