Which one of the following best expresses the main idea of the passage? A. The early music movement has yet to resolve a number of troubling questions regarding its approach to the performance of music. B. The early music movement, while largely successful in its approach to the performance of medieval and baroque music, has yet to justify its use of obsolete instruments in the performance of music by Beethoven and Mozart. C. The early music approach to performance often assumes that composers write music that is perfectly tailored to the limitations of the instruments on which it will be performed during their lifetimes. D. Although advocates of early music know much about the instruments used to perform music at the time it was composed, they lack information regarding how the style of such performances has changed since such music was written. E. The early music movement has not yet fully exploited the knowledge that it has gained from playing music on instruments available at the time such music was composed.