What is the role of the 4th paragraph in the development of the topic？A．To illustrate that

What is the role of the 4th paragraph in the development of the topic？

A．To illustrate that fertility rates in some highly developed countries began to rise.

B．To show that countries like Canada and Japan remain low fertility rates.

C．To explain how demographic transition occurred from 1975 to 2005.

D．To indicate that the trend of HDI is unrelated to the rise or fall of fertility rates.

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