Earthquakes would be the correct answer
The united states is going to see a big population growth compared to japan and other countries because alot of immigration is happening both legally and illegally to the united states and will see a population surge of more than 5 billion population growth within 2 years
There are 4 main large islands
I would put option A.
The question says how the surface MIGHT change over a long period of time so that's why I wouldn't say option C, and that's how canyons are formed if I'm not mistaken.
I hope this helps. My apologies if I'm wrong.