At what ages were Romans considered adults?

For ancient Romans, a boy became a man at 16.

Explanation :

There was a public festival, the Liberalia on March 17, at which boys donned the toga virilis (also called the toga pura or toga libera, pure and free respectively), the toga of manhood. Beforehand, at home in front of their family altar, a boy would remove his bulla, a protective charm necklace that allegedly warded off the evil eye, remove the toga praetexta, or toga for children, and soon after he would enter the army for his mandatory military service.

i hope this helps!

the answers is b.   environments.