Which of the Following Is the Best Definition of a Collection

Which of the following is the best definition of a collection policy.

A) A compilation of accounts receivable by the age of each account.
B) Wholly owned subsidiary that handles credit extension and receivables financing through commercial paper.
C) A discount given for a cash purchase.
D) Procedures followed by a firm in collecting accounts receivable.
E) Conditions on which a firm sells its goods and services for cash or credit.