An Information Systems Security Officer (ISSO) has been placed in charge of a classified peer-to-peer network that cannot connect to the Internet. The ISSO can update the antivirus definitions manually, but which of the following steps is MOST important?
A. A full scan must be run on the network after the DAT file is installed.
B. The signatures must have a hash value equal to what is displayed on the vendor site.
C. The definition file must be updated within seven days.
D. All users must be logged off of the network prior to the installation of the definition file.