Detailed Explanation:

Answer: Option 4 — a credit system granted by IMF to its members

The Reserve Tranche (formerly called Gold Tranche) represents the first 25% of a member country's quota with the IMF that can be withdrawn automatically without conditions, interest, or IMF approval. It acts as an unconditional credit facility available to member nations facing balance of payments difficulties, making it distinct from regular IMF lending programs which require strict conditionalities.

📝 Short Notes: IMF Reserve Tranche and Member Quotas

• Reserve Tranche: The portion of a country's IMF quota (typically 25%) that can be accessed unconditionally, without interest charges or policy conditions. Previously termed "Gold Tranche" when quotas were partly paid in gold.
• IMF Quota System: Each member country is assigned a quota based on its relative size in the global economy, which determines its financial commitment to the IMF, voting power, and access to IMF financing.
• Quota Composition: Members pay their quota partly in Special Drawing Rights (SDRs) or widely accepted currencies (reserve tranche position) and partly in their own currency.
• Automatic Drawing Rights: Unlike credit tranches which require IMF approval and conditionalities, the reserve tranche can be drawn immediately when needed for balance of payments support.
• No Interest Charges: Drawings from the reserve tranche do not incur interest or service charges, distinguishing it from other IMF lending facilities.
• Voting Rights: A country's quota also determines its voting power in IMF decisions, with larger economies having proportionally greater influence.