Test analysis: Beijing is the most concentrated area of colleges and universities in China, with more than 120 museums and numerous stadiums. At the same time, many state-level literary and art groups are concentrated in Beijing, and the Bird's Nest, the National Grand Theatre and the National Library are all concentrated in Beijing, which shows that Beijing is the cultural center of the country. So choose option a in this question.

Comments: It examines the urban functions of Beijing, which often appears in the multiple-choice questions of the senior high school entrance examination. Located at the junction of Taihang Mountain, Yanshan Mountain and North China Plain, Beijing is the capital of China, the national political, economic, cultural, transportation, scientific research and education center, and a world-famous historical and cultural city and international exchange center.