The main obstacle to a happy life for most of Humanity is not lack of intelligence but irrational or selfish impulses. That would be my D. Make a more liveable

The main obstacle to a happy life for most of Humanity is not lack of intelligence but irrational or selfish impulses. That would be my D. Make a more liveable world and no, we won't get there with more emotions/drama. More like live and let live. B won't expand human intelligence. C is paved with unintended consequences. Wait until it's not playing. So, IMHO, mostly A.