Final answer:
In single-user database systems, the transaction property that is not an issue is Isolation, since there is no concurrency that would require transactions to be isolated from each other.
Step-by-step explanation:
The student's question is concerned with transaction properties in database systems, specifically in single-user database systems. Transactions in databases are guided by the principles of Atomicity, Consistency, Isolation, and Durability (ACID). In a single-user database system, the property that is generally not an issue is Isolation. This is because the single-user environment eliminates the potential for transaction interference that could occur in multi-user systems where concurrent transactions are common. Hence, in a single-user context, there's typically no need to isolate transactions from one another, as they would not be executed concurrently.