Final answer:
Jerry may not need a license, but it's recommended to consult with a professional to ensure compliance with local laws.
Step-by-step explanation:
According to the law, in many jurisdictions, a real estate agent needs a license to show houses to potential buyers and negotiate sales. However, since Jerry is not a licensed real estate agent and is simply showing Bill's house while Bill is on vacation, he may not need a license. It's important to note that laws and regulations regarding real estate activities vary by jurisdiction, so it would be wise for Jerry to consult with a local attorney or real estate professional to ensure compliance.