Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions that follow.
BASKETBALL
Although he created the game of basketball at the YMCA in Springfield, Massachusetts, Dr. James A. Naismith was a Canadian. Working as a physical education instructor at the International YMCA, now Springfield College, Dr. Naismith noticed a lack of interest in exercise among students during the wintertime. The new England winters were fierce, and the students balked at participating in outdoor activities. Naismith determined a fast-moving game that could be played indoors would fill a void after the baseball and football seasons had ended. First, he attempted to adapt outdoor games such as soccer and rugby to indoor play, but he soon found them unsuitable for confined areas. Finally, he determined that he would have to invent a game. In December of 1891, Dr. Naismith hung two old peach baskets at either end of the gymnasium at the school, and, using a soccer ball and nine players on each side, organized the first basketball game. The early rules allowed three points for each basket and made running with the ball violation. Every time a goal was made, someone had to climb a ladder to retrieve the ball. Nevertheless, the game became popular. In less than a year, basketball was being played in both the United States and Canada. Five years later, a championship tournament was staged in New York City, which was won by the Brooklyn Central YMCA. The teams had already been reduced to seven players, and five became standard in 1897 season. When basketball was introduced as a demonstration sport in the 1904 Olympic Games in St. Luis, it quickly spread throughout the world. In 1906, a metal hoop was used for the first time to replace the basket, but the name basketball has remained.
Question: What does this passage mainly discuss?
