There are many good things you can do after someone has read your paper. The best thing to do would be : be polite, active, and ask questions that you know that the reader will be able to answer. So, the best answer would be A, I think, because you are asking what the reader enjoys best about your introduction, and you will later ask how you can improve your overall work. But yes, the first step you should take is ask how the reader enjoyed it, then ask for how to improve it.
