This page shows a list of links to explanation of the right answer to the problem. Follow each link in turn to see the explanation and to give your opinion on whether it helps you.
User:Martin_Hogbin/MHP - Not_the_original_choice
User:Martin_Hogbin/MHP - Combining doors
User:Martin_Hogbin/MHP - Parade
User:Martin_Hogbin/MHP - Economist