Which song, reaching #1 on the US Billboard Adult Contemporary chart in 1976, is based on the third movement from Symphony No. 2 by Russian composer Sergei Rachmaninoff?

"Never Gonna Fall In Love Again" is based on Rachmaninoff's 2nd symphony.

I was sitting around and listening to Rachmaninoff's 2nd symphony. I heard that beautiful melody. The reason that I used those things was twofold. First, they happened to move me. That stuff gave me goose bumps every time I listened to it. Also, I thought that it's a crime that there are some spectacular melodies in classical music that the general public doesn't get exposed to. I thought this was a way for me to bring some of the classical music that I love, incorporate it into a pop song for a new decade of kids, and introduce them to those beautiful melodies that they might not otherwise hear. That was the plan behind "Never Gonna Fall In Love Again."