In a multilevel security system (MLS), the Pump is:

A.
A one-way information flow device

B.
A two-way information flow device

C.
A device that implements role-based access control

D.
Compartmented Mode Workstation (CMW)

Explanation:
The Pump (M.h. Kang, I.S. Moskowitz, APump for Rapid, Reliable,
Secure Communications, The 1st ACM Conference on Computer and Communications
Security, Fairfax, VA, 1993) was developed at the US Naval
Research Laboratory (NRL). It permits information flow in one direction
only, from a lower level of security classification or sensitivity to a
higher level. It is a convenient approach to multilevel security in that it
can be used to put together systems with different security levels.
* Answer “A two-way information flow device” is a distracter.
* Answer “Compartmented Mode Workstation (CMW)”, the CMW, refers to windows-based
workstations that require users to work with information at different classification levels. Thus,
users may work with multiple windows with
different classification levels on their workstations. When data is
attempted to be moved from one window to another, mandatory access
control policies are enforced. This prevents information of a higher classification
from being deposited to a location of lower classification.
* Answer “A device that implements role-based access control”, role-based access control, is an
access control mechanism and is
now being considered for mandatory access control based on users’
roles in their organizations.