C

Most children can feed themselves with a spoon well before the third birthday—large cohort data show acquisition of this skill between about 7 and 18 months of age [Carruth, 2004, PMID 14702018]. In contrast, copying a square usually appears around 4 years [Brittain, 1976, PMID 1001092], hopping on one foot and reliably catching a ball are skills that continue to mature into the 4- to 5-year range [Howe, 2010, PMID 20463566]. Therefore, failure to feed with a spoon at age 3 indicates delayed development.