Free points y’all guys

What did not occur in the proterozoic eon a)the oxygen levels increase greatly in the atmosphere,b)the emergence of the eukarya , c)muti cella’s eukaryotic organisms began to diversify,d)anaerobic bacteria kept thriving with more oxygen

Diagram of the evolution of land plants?

In the sentence "a mining company will consider the distribution of coal when deciding how to mine the coal," what does the word distribution mean?