A

C. High levels of education.

Explanation:

A standard of living can be defined as the level of the population’s comfort, wealth, and the availability of goods and necessities. Standards of living are often used to compare countries or nations; for instance, in China, they may be higher than in Kenya because the economic advantages of these countries’ populations vary.

Such standards may be measured in multiple ways, including the level of education. The higher the level of education, the higher the standard of living in the country. Other criteria may include the gross domestic product (GDP) per capita, housing quality, and poverty rate. You can learn more about other characteristic of developed economies using the picture below.

Characteristics of developed economies compared to developing ones.
Characteristics of developed economies compared to developing ones (Source: www.icec-council.org)