I think the correct answer would be the third option. As the elements around the star begins to emit more and more electromagnetic radiation, the rocky materials are pulled in by the electromagnetic radiation. They are being drawn closer to the star and there would be a very high chance of a nuclear fusion could happen. The pressure and the temperature in a star is so high that it could allow nuclear fusion to happen. As a matter of fact, most of the life of a start is made from hydrogen nuclei fusing together forming a helium nuclei. As it runs out of the hydrogen nuclei, it would fuse other nuclei forming other elements.
