Which statement describes a pure situation?

A.
A situation that has an interval defined for evaluation.

B.
A situation that monitors an invalid user logon attempt.

C.
A situation that monitors only one disk free space attribute.

D.
A situation that becomes false when the condition that caused the event has changed.

Explanation:
http://publib.boulder.ibm.com/infocenter/tivihelp/v61r1/index.jsp?topic=%2Fcom.ibm.itm.doc
_6.3%2Finstall%2Fcust_itm_trig.htm