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Multiple ChoiceIntermediate 30s

Observer Pattern

Choose the best answer for: observer pattern
Options
  1. 1The observer replaces events by routing to one handler
  2. 2The observer is the same as a singleton with one listener
  3. 3The observer is a database that stores and polls subscriptions
  4. 4Observers subscribe to a subject and are notified of state changes
backendintermediate

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