Which of the following best accounts for the change in the overall number of major cities between 200 and 400 c. e.?

(a) environmental changes as part of the little ice age
(b) the spread of buddhism from south asia to central asia and east asia
(c) the decline or collapse of classical empires in eastern and western eurasia
(d) the adoption of agriculture in previously uncultivated regions of the americas and sub-saharan africa

The decline or collapse of classical empires in eastern and western Eurasia best accounts for the change in the overall number of major cities between 200 and 400 C.E.

Option C

Explanation:

The Roman Empire was the highest political and social system in Western civilization at its height (c. 117 CE). By 285 CE the empire was larger than the Central Government in Rome, so the empire was divided into the western and eastern empires by Emperor Diocletian, R. 284-305 CE.

Yet, by raising Maximum (r. 286-305) to co-emperor, the kingdom was always as huge as it split it in half in about 285 CE in order to facilitate better management. In this way, he established the Western Empire and the Eastern Roman Empire.

Considering that a lack of detail was a major cause of the empire crisis, Diocletian announced that succeeds should be selected and accepted from the start of a person's reign.

The Generals Maxentius and Constantine are two of certain successors In 305 CE, Diocletian formally retired from control, and the tetrarchy fractured in rival empire regions to govern. Maxentius and Constantine forced the Empire back into civil war after the demise of Diocletian in the year 311 CE.