Listen to Piano Concerto No. 24 in C Minor, K. 491: III. Allegretto online. Piano Concerto No. 24 in C Minor, K. 491: III. Allegretto is an English language song and is sung by Denis Matthews. Piano Concerto No. 24 in C Minor, K. 491: III. Allegretto, from the album Classical Music to Make You Smarter, was released in the year 2014. The duration of the song is 8:11. Download English songs online from JioSaavn.