The correct answer is option B, Planet Earth
Reason-
Here the world common is used to represent the planet earth and all the resources which are present on it. The world population has reached a mark of 7 billion which is putting excessive burden on the existing resources of planet earth be it air, water, land etc, Since the existing and limiting resources are getting exhausted, the planet earth is getting stressed. Since the planet earth is getting stressed all its resources including the human population itself is at the verge of a tragedy.