The Gaj Utsav-2023, a celebration focused on elephants, was inaugurated by the President of India, Smt. Droupadi Murmu, in April 2023. The event was held at Kaziranga National Park, which is located in Assam and is famous for its population of the Indian one-horned rhinoceros as well as being a significant elephant habitat.
Thus, the correct answer is (4) Kaziranga National Park.