Which statement is true about an if-then rule evaluation?

Which statement is true about an if-then rule evaluation?

A.
It can be evaluated more than once.

B.
It is evaluated once and only once.

C.
It must evaluate only native variable types.

D.
It cannot change the assessment for another if-then rule.

Explanation:
http://www.oracle.com/partners/en/knowledge-zone/applications/soasuite11g-1877659.pdf