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?

The correct option is 1, 2 and 4 (Italy, Japan, and South Korea).

To understand why this is the correct answer, we can analyze the demographic trends of each of the countries listed in the question:
1. Italy: Italy has one of the oldest populations in the world and one of the lowest birth rates in Europe. The country is frequently in the news due to its declining population, shrinking workforce, and the economic challenges associated with an aging society.
2. Japan: Japan is highly prominent in global media for its severe demographic challenges. It has a super-aged society where more than 28% of the population is aged 65 or older. The country has experienced a continuously declining birth rate and a shrinking total population for years.
3. Nigeria: Nigeria is in stark contrast to the aging nations. It has one of the youngest and fastest-growing populations in the world, with a high fertility rate, and is not associated with population decline or aging challenges.
4. South Korea: South Korea frequently breaks its own record for the world's lowest total fertility rate (well below the replacement level of 2.1 births per woman). It is heavily discussed in the media for its looming demographic crisis, rapid aging, and projected population collapse.
5. South Africa: South Africa has a relatively young demographic profile compared to European and East Asian nations, and it is not frequently highlighted in the media for population decline or aging population concerns.

Therefore, among the options given, Italy (1), Japan (2), and South Korea (4) are the countries globally recognized and frequently mentioned in media for their low birth rates, aging populations, or declining populations.