Final answer:
The economic union comprised of Belgium, Luxembourg, and the Netherlands is called the Benelux Agreement. It was signed in 1944 as an economic pact to promote cooperation and unity among the three countries after World War II.
Step-by-step explanation:
The economic union comprised of Belgium, Luxembourg, and the Netherlands is called the Benelux Agreement. It was signed in 1944 as an economic pact to promote cooperation and unity among the three countries after World War II. The Benelux Agreement served as a successful example of unification and played a crucial role in their economic recovery.