The US government developed several financial plans in the 1920s to help European countries pay their war expenses. Which of these plans extended Germany’s payoff period all the way to 1988?

The financial plan in the 1920s that extended Germany's payoff period all the way to 1988 was the Young Plan.

Explanation:

The Young Plan was the last of the reparation plans that regulated the payment obligations of the German Reich based on the Treaty of Versailles. It was negotiated by a panel of international financial experts in Paris from February to June 1929, and the final formulation was given at two government conferences in August 1929 and January 1930 in The Hague. It came into effect on May 17, 1930 retrospectively as of September 1, 1929 and set an average annuity of around two billion Reichsmarks, most of which were to be paid in foreign currency. It was to last until 1988, but was suspended by the Hoover moratorium in June 1931 and lifted by the Lausanne Conference in July 1932.

Colony-a country or area under the full or partial political control of another country and occupied by settlers from that country.

Chesapeake bay- The Chesapeake Bay is an estuary in the U.S. states of Maryland and Virginia. The Bay is located in the Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula with its mouth located between Cape Henry and Cape Charles

Cash crop-a crop produced for its commercial value rather than for use by the grower.

Wampanoag-a member of a confederacy of American Indian peoples of SE Massachusetts.
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