Consider the following countries:

1. Italy
2. Japan
3. Nigeria
4. South Korea
5. South Africa Which of the above countries are frequently mentioned in the media for their low birth rates, or ageing population or declining population?

Japan is projected to experience a significant population decline, more than halving from its peak of 128 million in 2017 to less than 53 million by the end of the century. Japan already has one of the oldest populations globally and a high percentage of people over 100.

Italy's population is also expected to more than halve, decreasing from 61 million in 2017 to 28 million by the end of the century. Similar to Japan, Italy faces an ageing population, with over 23% of its population aged 65 and above in 2019.

Nigeria, along with other African countries, is experiencing population growth, contrasting the decline seen in other regions. Nigeria's population is projected to become the second largest globally, reaching 791 million people. This growth is expected to result in a large working-age population and increased GDP.

South Korea is facing a demographic crisis that poses a risk to its economic growth and social welfare system. The country's population of 51 million is projected to halve by the end of the century, with fertility rates potentially falling to 0.68 in 2024.

Therefore, Italy, Japan, and South Korea are frequently mentioned in discussions about low birth rates, ageing populations, and declining populations.

Hence option (a) is the correct answer.