Iwill mark you as brainlinest for correct

Hello There

A pamphlet from the Tobacco Company about the dangers of second hand smoke

Reason: 
The first one is incorrect because its from an air purifying company, so of course they will be biased and say smoking is bad
The second one is still biased because its from a respiratory council, so they will say smoking is bad for the lungs because they study the bad effects of smoking
The last one will be biased because its from someone who experienced it, so they will have a negative response to it.

This leaves the third option, which is correct because it is from the company itself, and its impossible to be biased towards yourself, and you know they mean it.

I hope this helps
-Chris

The answer to your question is D.

Hope you are satisfied with the answer.

If you aren't satisfied then refer to me in the comments section...

:)