What Is the Reason That Emerging Adulthood Has Become a Lifespan

What is the reason that emerging adulthood has become a lifespan stage?

A) Less industrialized countries have pushed younger adolescents into later adult stages early.
B) More industrialized countries have pushed younger adolescents into later adult stages early.
C) Less industrialized countries have reduced the need for early transition to adulthood, creating a gap stage.
D) More industrialized countries have reduced the need for early transition to adulthood, creating a gap stage.