Final answer:
To sell spaces at a membership campground, one would likely need to have a Real Estate License, as this involves real estate transactions.
Step-by-step explanation:
To sell spaces at a membership campground, the required certification is usually a Real Estate License. This is because selling campground spaces involves real estate transactions. Individuals selling real property or offering memberships that include an interest in real property typically need to be licensed real estate agents or brokers. The other options, such as CPR Certification, Teaching Certificate, and Chef Certification, are unrelated to the sale of real estate and would not be required for this specific purpose.