Permian extinction happened at the end of the Paleozoic Era, this was before humans and also before dinosaurs, so options C and D cannot be causes of the mass extinction.
It's believed that, among the causes of the Permian extinction, there was volcanic activity, that launched carbon dioxide into the atmosphere, ocean anoxia, ocean acidification, and liberation of greenhouse gases from the ocean because of the movement of the tectonic plates, which caused a rise of the temperature.
This means that the correct answer would be B, plate tectonics.