=+ 4. Infantile amnesia best explains why

a. Justina, age 25, cannot remember hearing Japanese when she was 10.

b. Ella, age 10, has no memories of her third birthday party.

c. Karla, age 3, can't understand why her new brother is crying.

d. Becka, age 2, is unable to remember where she left her doll.

e. Hannah, age 6, can't remember the gymnastics routine she just learned.