In which of the following eras did life originate?

Which of the following was most likely to have been absent in free form in the primordial atmosphere at the time of the origin of life?

Following are the two statements regarding the origin of life.
$(A)$ The earliest organisms that appeared on the earth were non-green and presumably anaerobes.
$(B)$ The first autotrophic organisms were the chemoautotrophs that never released oxygen.
Of the above statements,which one of the following options is correct?

Which rays caused the dissociation of water into hydrogen and oxygen during the early stages of Earth's atmosphere?

Who first conducted an experiment on evolution to prove the biochemical origin of life?

The basis of the origin of life is now considered to be .......