Company M Assigned a Receivable from AB to the XY

Company M assigned a receivable from AB to the XY Finance Company on a "non-notification" basis. On this basis:

A) XY need not tell M when AB makes payment to M.
B) AB will make payment to M.
C) AB need not make further contact with M about the payment situation.
D) M need not tell XY when AB makes payment to M.