You create Microsoft Windows-based applications. You are changing an application to manage the daily activities of doctors and nurses in a hospital. The application will run on a single machine at the hospital front desk. The application will run 24 hours a day, seven days a week. Initial testing shows that the application consumes a lot of resources and that it runs out of memory intermittently. You want to change the application so that an alert is sent when memory usage is nearing the point of failure. An external application will be used for sending the alert. You need to decide what monitoring mechanism to use. You also need to ensure that the least amount of changes is introduced in the application. What should you do?

A.
Create a performance counter to monitor memory. Raise an event when memory reaches the critical value.
Change the external application to subscribe to the event.

B.
Create a performance counter to monitor memory. Call the external application when the counter reaches the critical level.

C.
Use the existing memory performance counters in the operating system. Call the external application when the counter reaches the critical level.

D.
Use the existing memory performance counters in the operating system. Use system monitor to create an alert to launch the external application when the counter reaches the critical level.