Definitely gonna be the 3rd one is your answer
The question can be changed into a new form:
Which element has the most negative electron affinity, or attraction for electrons? halogens have the highest electron affinities, and thus are more attracted to the electrons in the Hydrogen atom than any element in their respective periods.
In this case all the following choices are in the same period, thus Cl or Chlorine is the answer as it is a halogen.
I don't think so. No way that I know anyway. It it could be done then the need for more coal to be mined would have stopped hundreds of years ago. Once coal is burned, it forms water and carbon dioxide (essentially) with some sulfur oxides.
How do you put that back together again. It's a little like humpty dumpty.