Assertion:. The annual rate of population change of the world between 2010-2015 remained low at around 1.2%.
Reasoning: This low growth rate of population has resulted in decline in world population.

Assertion (A) is true but Reasoning (R) is not correct.

The correct answer is option 3: Assertion (A) is true but Reasoning (R) is not correct.

Assertion:. The annual rate of population change of the world between 2010-2015 remained low at around 1.2%. This is correct.
Reasoning: This low growth rate of population has resulted in declining trends in world population. This is incorrect. Low growth rate implies a slowing down of the rate at which the population is increasing, but it does not necessarily mean a decline in the population itself. If the population growth rate is positive, albeit low, the population will continue to increase, albeit at a slower pace. When a small annual rate is applied to a very large population, it will lead to a large population change. Even if the growth rate continues to decline, the total population grows each year.