What era of geologic time ended with the largest extinction event in earth history?

It seems that you have missed the necessary options for us to answer this question, but anyway here is the answer. The era of geologic time that ended with the largest extinction event in earth history is called the PALEOZOIC ERA, or also known as the Permian–Triassic extinction event. In this era, more than 90 percent of marine organisms became extinct. Hope this helps.

Ithink that b is correct but just in case wait to see if someone else answers