Select the option that can be used as a one-word substitute for the given group of words. The period of time in a person's life when they are developing into an adult

The correct option is Adolescence.

Explanation:
Let's look at the definitions of the options provided:
• Adolescence: The period of time in a person's life when they are developing from a child into an adult.
• Adultery: Voluntary sexual intercourse between a married person and a person who is not their spouse.
• Teenage: The state or age period of being between 13 and 19 years old.
• Childhood: The state or period of being a child, preceding adolescence.

Thus, the word that accurately replaces the given group of words is Adolescence.