A. The theremin is becoming a newly popular Instrument to play.
Explanation:
The above statement which is on the growing popularity of the instrument is the central idea in the passage. This is because, when the instrument was formed by the Russian physicist, its popularity grew small in the 1920's before it fades away. <em>Later in the 1990's, it was revived with so many composers creating good musics and symphonies using the instrument.</em>
