That was a really long answer, but absolutely correct. To simplify, just sit at the piano and find the set of 2 black keys in the center of your piano or keyboard. D is located between the 2 black keys. Middle C is located to the left of D.
Singing in a round is a fun challenge for voice students! This pretty song, "Come Away," can be sung with as few as 2 voices, or as many as 6. Free PDFs!!