The correct answer is (a) 11 July. 1987.
World Population Day is observed on July 11 every year to raise awareness about global population issues. It was established by the United Nations in 1989. The day commemorates the day on which the estimated world population reached five billion, which happened on July 11, 1987.
The world population is currently over 7.8 billion people. It is projected to reach 8 billion in 2023 and 9.7 billion in 2050. The rapid growth of the world population is putting a strain on the planet’s resources and environment. It is also leading to social and economic problems in many countries.
World Population Day is an opportunity to raise awareness about these issues and to promote sustainable development.