Of the Following Individuals, How Many Are in the Period

Of the following individuals, how many are in the period called emerging adulthood? Matthias, who is a 18-year-old college student; Toby, who is a 35-year-old businessman and single father of one daughter; Gunther, who is a 25-year-old law student; Liesl, who is a 13-year-old girl from a Jewish family and has recently celebrated her bat mitzvah.

A) 1
B) 2
C) 3
D) 4