Explanation:

The Indian Constitution is a blend of various constitutional features borrowed from different countries, adapted to India's unique context. - **Option A (Constitution of Japan):** Features like the 'procedure established by law' (Article $21$) and the functioning of the Supreme Court are influenced by the Japanese Constitution. However, the election process for Rajya Sabha members is not. - **Option B (Constitution of South Africa):** This is the correct answer. The procedure for the amendment of the Constitution (Article $368$) and the method of election of the members of the Rajya Sabha are significant features borrowed from the Constitution of South Africa. The system of proportional representation by means of the single transferable vote for Rajya Sabha elections is inspired by the South African model. - **Option C (Constitution of USA):** Several key features like Fundamental Rights, Judicial Review, Independence of Judiciary, Impeachment of the President, and the post of Vice-President were adopted from the US Constitution. - **Option D (Constitution of Ireland):** The Directive Principles of State Policy (DPSP), the method of election of the President, and the nomination of members to Rajya Sabha by the President (not their election) are borrowed from the Irish Constitution.