Concept:
The Veto Power in the United Nations is enjoyed exclusively by the five permanent members (P5) of the United Nations Security Council (UNSC).
Step 1: Recall the Permanent Members.
The five permanent members are:
• China
• France
• Russia
• United Kingdom
• United States
Each of these countries has the power to veto any substantive resolution of the Security Council.
Step 2: Analyse the options.
• Permanent members of the Security Council -- Correct.
• Non-permanent members of the Security Council -- Incorrect.
• Members of the General Assembly -- Incorrect.
• Judges of the International Court of Justice -- Incorrect.
Step 3: Final conclusion.
Hence, the veto power is exercised by the
\[
\boxed{\text{Permanent members of the Security Council}.}
\]