If its based on old or new english changes the qualities
In this sentence :
"You also learn what it takes to make money: a lot of effort.”
The main verb is "learn". The verb Takes is also a verb but since it is within the next clause and it is the verb of the Cataphoric refrence "it" such verb cannot be considered the main verb of the sentence.
So your final aswer is Learn.
Answer: I believe it’s A but I may be wrong, because it could also be B
