The term rhythmicity,in regard to infants,refers to

A) their ability to coordinate their actions,like looking and smiling,with those of a caregiver.
B) their tendency to sway in synchrony with music.
C) the production of cooing sounds in synchrony with music.
D) their biological regularity,as in how regularly they sleep or eat.

Rhythmicity

The predictability of an individual’s sleep, feeding, elimination, and other biological cycles. An aspect of infant temperament.

Biological Regularity

Patterns or rhythms observed in biological processes, such as sleep-wake cycles, that are consistent and predictable.

Cooing Sounds

Early vocalizations made by infants, typically consisting of soft, vowel-like sounds, and seen as a precursor to babbling.