In the united states, the most widely recognized marker of entry into adulthood is:

a. getting married
b. holding a more or less permanent, full-time job
c. moving into one's own home
d. having a child.

Option: b. holding a more or less permanent, full-time job.

Explanation:

In the United States, teenagers or people with 20s enter into adulthood when they became the permanent holder of full-time jobs. Permanent jobs in America is not easy to find because most of the companies hesitate to hire a permanent employee. In America, one out of three gets a permanent job. As people get jobs, they no longer depend on their parents for any support and consider to be old enough to take decisions.