A nurse is reinforcing teaching with a parent of a 4-month-old infant during a home visit. Which of the following statements by the parent indicates an understanding of the teaching?

"I will leave the plastic covering on the crib mattress."

"I will lay my baby's head on a pillow while he is in the crib."

"I will use a cool-mist vaporizer in my baby's room."

"I will leave my baby's bib on while he is sleeping."