Mandy Is Eight Months Old; Her Mother, Jennie, Is 40

Mandy is eight months old; her mother, Jennie, is 40 years old; and her grandmother, Matilda, is 70 years old. During a typical 24-hour period, who experiences the highest proportion of REM to NREM sleep?

A) Jennie
B) Matilda
C) Mandy
D) Mandy, Jennie, and Matilda all experience the same approximate proportion of REM to NREM sleep during a typical 24-hour period.