How many do you need? because there is more then one.
dictatorial power, forcible suppression of opposition and strong regimentation of society and of the economy
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.