Write a multi-choice question for the following article, with the given choices and answer: Article: There are many people who could be Olympic Champions. I'd estimate five million people could have beaten me in the pole-vault on the years when I won it, at least five million. Men were stronger, bigger, and faster than I could have done it, but they never picked up a pole, never made the efforts to vault their legs off the ground to try to get over the bar. Greatness is all around us. It's easy to be great because great people will help you. What was fantastic about all the conventions I went to was that the greatest in the business would come and share their ideas, their methods and their techniques with everyone else. I have seen the greatest salesmen showing young salesmen exactly how they did it. They didn't hold back. I have also found it true in the world of sports. I'll never forget the time I was trying to break Dutch Warmer Dam's record. I was about a foot below his record, so I called him on the phone. I said, "Dutch, can you help me? I seem to have _ . I can't get any higher." He said, "Sure, Bob, come on up to visit me and I'll give you all I got." I spent three days with the master, the greatest pole-vaulter in the world. For three days, Dutch gave me everything he'd seen. There were things that I was doing wrong and he corrected them. To make a long story short, I went up eight inches. That great guy gave me the best that he had. Great people will share. Great people will tell you their secrets. Look for them, call them on the phone or buy their books. Go where they are, get around them and talk to them. It is easy to be great when you get around great people. Options: A Because many great people also attended them. B Because they were supported by many great businessmen. C Because he learned to share his greatness with others. D Because great people were willing to share. Answer: D Because great people were willing to share. Question:
Why does the author think well of the conventions he attended?