Answer:
A. breakup of Pangaea
Explanation:
During the Mesozoic, the Pangaea broke up to become what became the continents today.
The Mesozoic era is between the Cenozoic and Paleozoic era.
After the Permian extinction, the Mesozoic era began. It was during this period in time that the super continent divided up. Also, at the part of this era, dinosaurs evolved and became extinct.