According to the Children's Defense Fund report of 2011, what differences are noticeable between low-income babies and higher-income babies by 9 months?

A) Differences in which kinds of car seats they had
B) Differences in the kind of formula they drank
C) Difference in development
D) Differences in how much they cried

According to the Children's Defense Fund report of 2011, noticeable differences between low-income babies and higher-income babies by 9 months were related to development. Specifically, low-income babies demonstrated slower cognitive, language and socio-emotional development than higher-income babies. Differences in car seats, formula, and crying were not highlighted in the report as significant factors.