Recent finding lend strong support to the theory that a black hole lies at the center of the Milky Way and of many of the 100 billion other galaxies estimated to exit in the universe. a. that a black hole lies at the center of the Milky Way and of b.that a black hole lies at the Milky Way's center and c.that there is ablack hole lying at the milky Way's center and d.of a black hole lying at the Milky Way's center and e.of a black hole that lies at the center of the Milky Way and of (a) 为什么这题是a 不懂a选项and 后面的of 是that a black hole lies at the center of the Milky Way and (that a black hole lies at the center) of 的意思吗 但是这样的意思怎么感觉怪怪的 | 
