Statement (i) is true. The Udayagiri and Khandagiri hills contain both natural rock shelters which were later modified and carved, resulting in a combination of natural and artificial caves. Statement (ii) is true. Udayagiri has 18 caves, and Khandagiri has 15 caves, totaling 33 caves. Statement (iii) is false. The famous Hathigumpha inscription of King Kharavela is located in Cave 14 (Hathi Gumpha or Elephant Cave) in Udayagiri, not Khandagiri.