The problem of international liquidity is related to the non-availability of

International liquidity refers to the availability of gold and "hard currencies"—widely accepted foreign exchange like the US Dollar, Euro, and Yen—required by countries to settle international trade deficits and debts. While gold (option b) was historically the primary medium under the Gold Standard, it is no longer the dominant component of modern international reserves, which now rely heavily on stable, convertible currencies and SDRs. The core concept being tested is the mechanism of international payments and the composition of global foreign exchange reserves.