One of the Difficulties with Determining the Impact of Non-Parental

One of the difficulties with determining the impact of non-parental care on infants and young children is that

A) extended parental benefits now allow parents to stay home during the critical or sensitive periods of brain and emotional development, altering their impact.
B) the quality and monitoring processes for daycares and licensed home-care providers negates any risk of negative impacts.
C) non-parental care is poorly defined and includes a wide range of providers, from grandparents to licensed daycares.
D) stress levels of working parents are so high that this issue is more important to research than non-parental care outcomes.