Sociologist: Climate and geology determine where human industry can be established. Drastic shifts in climate alwa...

I chose (A) "Climate is the primary cause of migration." Is this incorrect because it is too strong and we do not know if climate is necessarily the primary cause but perhaps just one of several potential causes? Also is answer (C) "A population remains settled only where the climate is fairly stable" correct because it is the logical opposite of the part of the stimulus "Drastic shifts in climate always result in migrations"? Thank you in advance for the help!