Final answer:
Country X is in the age of mass consumption based on Rostow's model if it has a high level of industrialization and advanced urban society, which are not characteristics of a large agricultural sector or low urbanization.
Step-by-step explanation:
Country X is likely to be in the age of mass consumption according to Rostow's development model if it demonstrates a high level of industrialization rather than a large agricultural sector or high income inequality.
In Rostow's five-stage model of economic development, a country reaches the age of high mass consumption at stage 5, which typically features an advanced urban society with a robust consumer economy.
The characteristics of such a society include substantial industrial activity, increasing living standards, and smaller family sizes due to urban growth and economic development. Given these trends, the features listed in the question, such as a high level of industrialization, would be indicators that a country is indeed on the higher end of Rostow's model, suggesting that it is a developed nation with a diversified economy. Meanwhile, a large agricultural sector or low level of urbanization would not be characteristic of stage 5 but rather of the earlier stages of development.