What common trait did early empires share regarding their economic systems?

Early empires often developed sophisticated economic systems that included the standardization of commerce and taxation. This standardization was crucial for several reasons: it facilitated trade across vast regions, ensured consistency in economic transactions, and enabled the collection of taxes that were necessary for maintaining the infrastructure and military of the empire.

Having a standardized system allowed for increased efficiency in trade, as merchants could operate under agreed-upon measures and values, which reduced confusion and disputes. Additionally, taxation methods would typically be established to provide resources for public projects, defense, and governance, thereby contributing to the stability and growth of the empire's economy.

The other options, while they may describe certain economic practices, do not encapsulate the broader and more defining feature shared by many early empires as effectively as the standardization of commerce and taxation.