The bottom two are correctly used, the top 2 are not.
Explanation:
A colon is correctly used for a list of items or normal nouns. However the top two are naming an order of events and a order of what needs to be found. This is not used for a colon since there used for a list not a period of time. The next part of the explanation is the bottom two use a list for things needed for a ballet school, and a list of things that make smog. That's the proper use for a colon.
Answer: I think it's incorrect, because they put a comma at the end of her sentence. It had a '...' already there, so why put the comma? Just what I think. I'm not entirely sure, though.
