Final answer:
The first stars, composed of hydrogen and helium, could not have formed rocky planets due to the lack of heavier elements. Supernovae, large clusters, and long-lived main sequence stars are all possible outcomes for these early stars.
Step-by-step explanation:
The very first stars that formed in the universe, also known as Population III stars, were composed primarily of hydrogen and helium, the elements produced in the Big Bang, with almost no heavier elements present. Hence, option 3) Some may have formed rocky planets around them cannot be true for the earliest stars because rocky planets require heavier elements like silicon and iron, which were not available in the necessary abundance at the time these first stars formed. Supernova explosions from some of these early stars eventually spread heavier elements throughout the universe, enabling subsequent generations of stars to support planet formation, including rocky planets.
Options 1), 2), and 4) are all possibilities for the first stars. Supernovae are a natural end for massive stars, and they were responsible for dispersing the necessary elements for later stars to have planets. The first stars could also have formed in large clusters, and some could still be on the main sequence if they were of sufficiently low mass to have long lifetimes.