Final answer:
The cognitive abilities of school-age children are best represented by their capacity to classify, group, sort, and consider concepts during decision-making, as per Piaget's concrete operational stage of development.
Step-by-step explanation:
The cognitive abilities of school-age children are best described by option B, which says that they have the ability to classify, group and sort, and hold a concept in their minds while making decisions based on that concept. This option aligns with Piaget's theory of cognitive development, specifically the concrete operational stage that typically defines the thinking patterns of children aged 7-11 years.
Option A describes a regression in cognitive development rather than an advancement, which is inconsistent with normal child development. Option C and D describe characteristics of formal operational thought, which occurs from age 12 and beyond. Thus, B is the sentence that best describes the cognitive capabilities of school-age children.