True or false? A design pattern is a collection of classes and interfaces that can be used as part of an application implementation. True False Which of the following are appropriate for a requirements document? Choose 4. Multiple users will be able to log on without experiencing conflicts or slow load times. The program will not have any bugs. If the systems detect a major issue, it will save state and restart. The user will be able to modify the location of the program's save location on their machine. The system shall be available to all users at normal working hours. Downtime within normal working hours shall not exceed five seconds in any one day. Each staff member using the system shall be uniquely identified by his or her 8-digit employee number. The questions 25 to 27 are based on the following problem scenario about design pattern: It is a remote control system. Our remote controller is the center of home automation and can control everything. For the moment, we just have a light as an example that we can switch on or off. We decide to use command design pattern for this system. The object "light" is Client Invoker Receiver ConcreteCommand The object "remote controller" is Client Invoker Receiver ConcreteCommand How many concrete command class(es) right now in this system? 1 2 3 4