Answer:
The correct answer is option d. "9 billion"
Step-by-step explanation:
The current world population is of 7.7 billion, and is growing at a slow but constant rate. By the year 2050, the world’s population is projected to be around 9 billion. The most recent estimations made by the United Nations have elevated this cipher to 9.7 billion, with half of the growth projected to take place in only nine countries.