An application where only one user accesses the database at a given time is an example of a(n) ________ .

Option A: single-user database application
This option is correct. An application where only one user accesses the database at a given time is known as a single-user database application. This type of application is designed for scenarios where database access is limited to one user, ensuring that data integrity and consistency are maintained without the complexities of handling multiple concurrent users.

Option B: multiuser database application
This option is incorrect. A multiuser database application allows multiple users to access the database simultaneously. It requires mechanisms to handle concurrent data access and ensure data consistency among all users.

Option C: e-commerce database application
This option is incorrect. An e-commerce database application typically supports multiple users accessing the database concurrently for transactions, product listings, and other e-commerce activities.

Option D: data mining database application
This option is incorrect. A data mining database application involves analyzing large sets of data to discover patterns and insights. It can support multiple users or automated processes accessing the database for data analysis.

Conclusion:
An application where only one user accesses the database at a given time is an example of a single-user database application, making Option A: single-user database application the correct answer.