Which of the Following Is the Best Definition of Lockboxes

Which of the following is the best definition of lockboxes?

A) The need to hold cash to take advantage of additional investment opportunities, such as bargain purchases.
B) Much like an automated teller machine card; one use is within corporations to control access to information by employees
C) Bank makes proceeds of cheques deposited available the same day before cheques clear.
D) The need to hold cash as a safety margin to act as a financial reserve.
E) Special post office boxes set up to intercept and speed up accounts receivable payments.