单项选择题 You work as an application developer at Certkiller .com. Certkiller .com uses an application that calculates monthly payments based upon client input. You are currently debugging this application using the Microsoft Visual Studio 2005 IDE. The application contains the following code: public double CalculateMonthlyPayment (Single rate, double principal) { //Implementation code } You have discovered that unexpected results are being returned by the application. You would like to pause execution and display a message box containing an error message in the event of a negative or zero rate value is Passed to the CalculateMonthlyPayment method. You need to ensure that this only occurs during debugging mode. What should you do?（）

单项选择题 You are required to launch the App.exe process, and specify sample.txt as the input file. App.exe will then use the contents of sample.txt to establish the environments current settings. You need to ensure that the code you use meets these requirements. What should you do?（）

单项选择题 You would like to create a custom performance counter for an application that you created recently. To do this, you decide to create a custom category named ApplicationPerformance and a performance counter named HitNumber. You need to ensure that this counter is shared across numerous applications. What should you do?（）