Answer: C. Devastation
Step-by-step explanation:
Cataclysm refers to an event which brings about a great change or harm. It is an event that leads to destruction or a violent change. Its synonyms include cdisaster, collapse, destruction, devastation, catastrophe, etc.
The accurate synonym for cataclysm as it is used in the excerpt is devastation. It implies that the animals that had survived the initial devastation were eventually killed.