while Earth's continents were joined while Earth's habitats were stable before major climatic changes following mass extinctions
I gave my students this multiple choice question: According to the fossil record, when did episodes of rapid speciation commonly take place?

Only one answer is correct among these 4 choices:
- while Earth's continents were joined
- while Earth's habitats were stable
- before major climatic changes
- following mass extinctions

Could you tell me which one is correct?

following mass extinctions