Cоnsider the fоllоwing TemperаtureSensor clаss. Which of the following design pаttern is used in the TemperatureSensor class? Assume that TemperatureStation class has been designed and implemented correctly. public class TemperatureSensor { private List weatherStations = new ArrayList(); private String temperature; public void addTemperatureStation(TemperatureStation station) { weatherStations.add(station); } public void removeTemperatureStation(TemperatureStation station) { weatherStations.remove(station); } public void notifyStations() { for (TemperatureStation station : weatherStations) { station.update(temperature); } } public void setTemperature(String currentTemp) { this.temperature = currentTemp; notifyStations(); }}