Which of the Following Statements Concerning Mail-Based Collection Systems Is

Which of the following statements concerning mail-based collection systems is true?

A) Regardless of recent developments in payment processing equipment,it is still too expensive for smaller companies to use mail-based collection systems.
B) Generally it is cheaper for high-volume processors to use the lockbox system rather than mail-based collection systems.
C) Low-volume processors may find that using a lockbox system is more cost effective than a mail-based collection system.
D) All of the above statements are true.
E) Only (a) and (b) are true.