D) Ancient times.
Think about what an "economy" is. An economy is the production, distribution, and consumption of goods and services by humans in society. So as long as there have been humans operating together in society, "economies" have existed. In both ancient times and modern times, in tribal societies the activities in the economy may be simple things like raising crops and herding or hunting animals to feed oneself and trade with others. In more complex societies, various forms of technology and advancement will be added to the economic picture. Ancient societies such as Egypt and Babylon pursued large building projects, etc.
"Economy" comes from the Greek word οἰκονομία (oikonomia), which means "the order of the household." As long as there have been households and groups of households in human society, there have been economies operating.
