The correct answer is C
control foreign trade
Foreign trade control is an example of a shared power because it is shared between the legislative and the executive. For the USA to enter into any agreement with foreign entities, the agreements must be ratified by congress.
The 13th Amendment is to abolish (rid) slavery. I'm not understanding the question as to what the purpose was. Can you be more specific or did you just need to know what it was?
Christopher Columbus was the first
I believe an Initiative is C. A vote on a legislative measure.