Some people understand the famous saying "If you don't reach the Great Wall, you will not be a hero. ". Assuming this understanding is true, which of the following judgments must be true? ['People who reach the Great Wall must be good guys.', 'If he is a man, he must have been to the Great Wall.', 'Only a good man has been to the Great Wall.', 'Without the Great Wall, he will be a good man.']