The 1987 exchange-rate agreement question is not correctly answered by the Plaza Accord: the Plaza Accord was signed in 1985, while the 1987 agreement was the Louvre Accord.
The Louvre Accord was announced in Paris on February 22, 1987, by the finance ministers and central-bank governors of the Group of Six major economies. Its purpose was to stabilize exchange rates after the sharp dollar depreciation encouraged by the Plaza Accord.
The agreement is relevant to financial-market history because international currency coordination shaped interest rates, trade expectations, and investor decisions during a period of major market volatility. It was not itself a stock-market crash. The famous October 1987 equity collapse occurred later that year and had additional causes, including valuation concerns, monetary conditions, and automated trading strategies.
This distinction matters because the two accords are frequently confused. The Plaza Accord sought to push the U.S. dollar lower, whereas the Louvre Accord sought greater exchange-rate stability. The wording of this question therefore identifies the Louvre Accord, not the earlier Plaza agreement.