The correct word you are looking for is Collectivization
The following sentence contains an adverb clause.
This sentence contains two clauses - an independent clause (We moved) and a dependent/subordinate clause (because our house was too small). Given that the second sentence gives us a reason why they moved, it acts as an adverb, which is why it is an adverbial clause.
I Would suggest reposting this again, just make the screenshot more zoomed in on the assignment, it is very hard to read
im not completly sure but i would say that the awnser is b.