"Preference Payments" Made by the Debtor to One Creditor to the Detriment

"Preference payments" made by the debtor to one creditor to the detriment of all other creditors within 90 days before the bankruptcy petition was filed:

A) are reduced from the monies available to the general unsecured creditors.
B) are usually written off.
C) may be recovered and returned to the cash available for all creditors.
D) are not recovered,as management assurances are binding.