What human development period 2 years and 12 years called

In these lessons, students become familiar with the four key periods of growth and human development: infancy (birth to 2 years old), early childhood (3 to 8 years old), middle childhood (9 to 11 years old), and adolescence (12 to 18 years old).

the answer is a! (2.9 x 10^-18 j) hope i could someone. : )