The correct option is III only. Statement III accurately reflects the provision that mandates a minimum age of forty-five years for the Chairperson or Members of the Lokpal, aligning with the constitutional requirement for such positions to ensure experienced leadership. In contrast, Statement I is incorrect because Lokpal's jurisdiction does extend to public servants abroad, Statement II mistakenly restricts the Chairperson to the Chief Justice of India (it can also include retired judges), and Statement IV is incorrect as the Lokpal can indeed investigate allegations against a sitting Prime Minister in certain circumstances, especially post-tenure for actions not related to parliamentary proceedings. Understanding these principles is crucial for grasping the structure and functions of anti-corruption bodies in Indian governance.