Concrete Operational Stage in Cognitive Development

Jean Piaget proposed a theory of cognitive development that describes how children progress through distinct stages of thinking. One of these stages, known as the 'Concrete Operational Stage,' occurs typically between the ages of 7 and 11 years. During this stage, children begin to think logically about concrete events and understand the concept of conservation. Which of the following best exemplifies a skill that a child would demonstrate during the Concrete Operational Stage?