Final answer:
Participation as a subscriber is mandatory pursuant to the rules of REIX.
Step-by-step explanation:
The correct statement regarding participation in REIX is II) Participation as a subscriber is mandatory pursuant to the rules.
REIX stands for Real Estate Information Exchange, and it is a system that allows for the sharing of property listing information among real estate professionals. As per the rules of REIX, real estate brokerages must participate as subscribers. This means that they are required to join and use the system to access and share property listing information.
Therefore, option II correctly states that participation as a subscriber is mandatory for real estate brokerages under the rules of REIX.