根据短文内容，选择最佳答案。
During his life Dr James Naismith worked as a doctor, taught P.E and wrote several books. While he never thought it very important, Dr Naismith is today best known for one thing. He was the inventor of basketball.
Dr James Naismith was born in Canada in 1861 and his first job was at a special sports school in the USA.
One day the school principal（校长） told James he was having a problem with the students. Because of heavy snow, the students could not go outside. He told James that they needed a sport the boys could play indoors and gave the teacher two weeks to think of something.
It was on the very last day that James came up with his idea. The "birth of basketball" is said to be on December 21, 1891, when two teams from the school played the first game. It was quite different from the basketball games of today. It had 9 players on each team and footballs were used instead of basketballs. Soon after, the game changed to 5 players on each side, using special "basketballs" through nets.
Although Dr Naismith did not live to see basketball become the worldwide game it is today, in 1936, just three years before his death, basketball became an Olympic sport at the games in Berlin.
