Final answer:
A non-resident Colorado broker is not required to maintain a place of business in Colorado, and the requirement to pay a referral fee is not mandatory, but often practiced.
Step-by-step explanation:
In regards to a non-resident Colorado broker, the correct answer is 2) Not required to maintain a place of business in Colorado. Under Colorado's real estate licensing requirements, a non-resident broker may conduct business within the state without having a physical office location there. However, they must comply with all other aspects of Colorado's real estate regulations, including licensure and working through Colorado-licensed brokers for transactions within the state. Thus, the requirement to pay a referral fee is not a mandatory condition for non-resident brokers; however, it is a common practice for out-of-state brokers to engage in referral agreements with local brokers when dealing with clients interested in Colorado properties.