The correct answer is option 2, Ellora. While options 1, 3, and 4 are all significant locations related to the Rashtrakutas, Ellora was the early capital of the Rashtrakutas. Sopara, mentioned in option 1, was an important port town in ancient India, but it was not the capital of the Rashtrakutas. Vatapi, mentioned in option 3, was the later capital of the Rashtrakutas, after they moved from Ellora. Ajanta, mentioned in option 4, is famous for its rock-cut caves and paintings, but it was not the capital of the Rashtrakutas. Therefore, option 2, Ellora, is the correct answer as it was the early capital of the Rashtrakutas.