Zollverein was a customs union initiative led by Prussia that played a vital role in the economic and subsequently political unification of Germany.
The correct statement in regard to Zollverein is option B: It was a customs union formed at the initiative of Prussia and joined by most of the German states. Established in 1834, the Zollverein, or German Customs Union, was a coalition of German states brought together under Prussian leadership to manage customs and economic policies within their territories. This was a step towards the economic unification of Germany which later became a political unification.
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