Final answer:
The circumstance that does NOT require agent disclosure is when a licensee owns several investment properties and is selling one as part of his own corporation.
Step-by-step explanation:
In the given options, the circumstance that does NOT require agent disclosure is option a) As part of his corporation, Sean, a licensee, owns several investment properties. He's selling one.
Agent disclosure is the process of revealing any relevant information about a real estate transaction to all parties involved. In this case, Sean owning several investment properties and selling one does not require agent disclosure because he is acting on behalf of his own corporation and not representing any other party.