Where Must the Signature Appear on a Negotiable Instrument in Order

Where must the signature appear on a negotiable instrument in order to meet the signature requirement?

A) anywhere on the face of the instrument
B) anywhere on the face of the instrument or anywhere on the back of the instrument
C) on the face only, and only at the end of the instrument
D) anywhere on the face, or in the proper indorsement place on the back
E) at the end of the instrument on the face, or in the proper indorsement place on the back