单项选择题 您需要编写可接受日期时间参数并返回一个布尔值，多路广播的委托。您应该使用哪个代码段？（）

单项选择题 You develop a service application named PollingService that periodically calls long-running procedures.These procedures are called from the DoWork method.You use the following service application code：   When you attempt to start the service， you receive the following error message： Could not start the PollingService service on the local computer.Error 1053： The service did not respond to the start or control request in a timely fashion. You need to modify the service application code so that the service starts properly.What should you do？（）

单项选择题 You are developing an application that runs by using the credentials of the end user. Only users who are members of the Administrator group get permission to run the application. You write the following security code to protect sensitive data within the application.bool isAdmin=false；  WindowsBuiltInRole role=WindowsBuiltInRole.Administrator； ......  if（!isAdmin）          throw new Exception（"User not permitted"）；   You need to add a code segment to this security code to ensure that the application throws an exception if a user is not a member of the Administrator group. Which code segment should you use？（）