No. 6 in B Flat-B-Dur, BWV 1051 / II. Adagio ma non tanto

Whose song is No. 6 in B Flat-B-Dur, BWV 1051 / II. Adagio ma non tanto?

Artist Album
Johann Sebastian Bach (1685-1750)
Brandenburg Concertos No
Brandenburg Concertos Nos. 4-6