Final answer:
The correct answer is option b. The Permian extinction, which occurred about 251 million years ago, resulted in the extinction of about 96% of all marine animals.
Step-by-step explanation:
The Permian extinction, which occurred about 251 million years ago, resulted in the extinction of about 96% of all marine animals. This extinction event is known as the end-Permian extinction, and it was the largest in the history of life on Earth.
The causes of this mass extinction are believed to be extended and widespread volcanic activity that led to a runaway global-warming event, causing the oceans to become largely anoxic and suffocate marine life.