The correct option is A A - 2, B - 3, C - 1
Paul Ehrlich proposed the rivet popper hypothesis. The hypothesis explains the effect of decrease in biodiversity on the ecosystem. It is an analogy where the ecosystem is compared to an airplane and species are compared to the rivets linking the various parts of the airplane.
If every passenger starts to pull out or pop a rivet to take home, it may not have any affect on the safety of the flight initially. But as more and more rivets are removed, the safety of the plane is compromised over time. Additionally, if the rivet belongs to a crucial part of the plane such as the wings, it will pose a serious threat to the safety of the flight.
Similarly in an ecosystem, loss or extinction of a species (analogous to rivets) from the ecosystem, will not create any threat to the existing species initially, but the extinction of key species (analogous to rivets on the wings), will become a threat to the safety of other species (analogous to flight safety).
For example, removing a predator like lion from an ecosystem will result in the increase in the number of the prey species (deer, rabbits). This will result in competition between them for the same limiting resources, eventually leading to their demise.