Research Has Shown That Young Infants Do Not See Detail

Research has shown that young infants do not see detail at a distance as well as adults do and need more contrast than adults in order to see well. According to the text, what research method was used? ​

A) assessment of anxiety levels when the primary caregiver is at various distances
B) observation of facial expressions and head movements as well as the duration and intensity of suckling during feedings
C) measurement of the amount of time the baby spends viewing a pattern rather than a uniform screen
D) qualitative interviews with parents and other caretaking adults