What action may the Commissioner take if someone is fraudulently using another builder's license number?

The Commissioner has the authority to address fraudulent activities seriously, especially when a builder's license number is being misused. When someone is fraudulently using another builder's license number, the Commissioner can issue a Cease and Desist Order, which immediately halts any ongoing work associated with that fraudulent activity. Moreover, the actual license holder is at risk of having their license revoked since their license has been compromised through the fraudulent use.

Additionally, both parties involved can be subject to fines as a legal repercussion for their actions. This approach ensures that the integrity of licensure in the building industry is upheld and acts as a deterrent against further fraudulent activities.

The other potential actions, while they may apply in different contexts, do not encompass the full range of consequences that the Commissioner can enforce as outlined in the correct answer. Therefore, the comprehensive approach of option B highlights the severity of the situation and reflects the regulatory framework in place to maintain ethical practices within the construction industry.