context: Krakatau (or Rakata) is an active volcanic archipelago and is in the Sunda Strait, between Java and Sumatra. This name is also pinned on a volcanic peak there (Mount Krakatau) which vanished due to cataclysmic eruptions on August 26-27 1883. In 2019, the area which is now a nature reserve has four small islands : Rakata Island, Anak Krakatau Island, Sertung Island, and Panjang Island (Rakata Kecil). Based on geological studies, all of these islands originate from the Krakatoa single volcanic system that has existed in the past.
question: what is the number of islands in the Krakatoa archipelago?
answers.text: four