The one that could affect human population would be :
A. Deadly virus emerges that can pass from human to human.
This will greatly decrease the amount of human population
C. Nuclear war breaks out between two nations
This will kill a lot of people and also potentially creating genetic mutations for the next generation
D. Immigration to united states from china increases
This will make it harder for the population to get the resources that they need for their living
hope this helps
I believe the answer is: Executive stage
According to schaie, Executive stage refers to the period when people started to develop the need to perform complex responsibilities.
People in this stage tend to be ready for leadership position and usually happen between the age of 35-60.
Through conquests, expansion, construction of free entertainment, etc.