According to the Bharatiya Sakshya Adhiniyam, 2023, which of the following is not a competent witness?

Under section 124 of the Bharatiya Sakshya Adhiniyam, 2023 (formerly section 118 of the Indian Evidence Act, 1872) and its Explanation, a deaf, dumb or minor witness—and even a person of unsound mind—is competent to testify unless prevented from understanding the questions put to him and giving rational answers to them; thus "A person of unsound mind prevented from understanding questions and giving rational answers" is not a competent witness.