Personally , I think A is the best. It has facts (less expensive, close) and it doesn’t have too much opinion. Rather than “everybody likes animals” or “my favorite animals live in the reptile house” it shows that it’s practical and fun!
D. A place is concise red a desert if it gets less than 10 inches of rain per year
One drawback of voluntary trade is that it can make one group dependent upon another for necessary goods.
I think the purpose of an author is a new story inspiration.