When advertising a high number of completed transactions, what must Salesperson Brown include?

When advertising a high number of completed transactions, Salesperson Brown must include what is meant by the term "transaction" regarding the claim. This is important because the term "transaction" can vary in meaning and scope, so clarifying it ensures that potential clients have a clear understanding of the claim being made. Providing this information adds transparency and credibility to Brown's advertisement.

Option B is incorrect because details of all properties involved in the transactions do not need to be published when advertising a high number of completed transactions. This could potentially breach client confidentiality and privacy laws.

Option C is incorrect because Salesperson Brown does not need to get approval from the Registrar before advertising the claim of a high number of completed transactions.

Option D is incorrect because it is allowed to mention the number of transactions when advertising, as long as it is accompanied by an explanation of what "transaction" means in that context. It is not limited to only advertising the sales volume in dollars.