Explanation
Correct answer: B.
Choice B is the best answer because it best describes the main purpose of the text. The text indicates where and when jazz tap first developed (in African American communities in the 1920s) and what influenced it (the quick rhythms and improvisations in jazz music) and then explains that it evolved alongside jazz music in the 1930s and 1940s, resulting in a very different form of tap dance than had existed before. Therefore, the main purpose of the text is to discuss jazz tap’s development.
Why the other choices are wrong
Choice A
Choice A is incorrect. Although the text indicates that jazz music became widely popular in the US in the 1920s and describes some of jazz music’s qualities, the text never explains why audiences prefer some kinds of music—jazz or otherwise—over others.
Choice C
Choice C is incorrect because the text never mentions any musical instruments and doesn’t describe how to play one.
Choice D
Choice D is incorrect because the text discusses jazz tap generally and never identifies a particular dancer, famous or otherwise.