Which of the following is a sign of emotional development in children?

Developing self-control is considered a significant sign of emotional development in children. This aspect of development refers to a child's ability to manage their emotions, actions, and behaviors in various situations. It encompasses skills such as regulating impulses, understanding appropriate social responses, and responding to emotional experiences with resilience. Self-control is crucial for a child's interpersonal interactions, helping them navigate social environments and relationship dynamics as they grow.

The other options reflect different developmental milestones but are primarily focused on physical or cognitive growth rather than emotional skills. Learning to walk and mastering crawling are important physical milestones that reflect motor development. Understanding physical boundaries involves cognitive skills related to spatial awareness and safety but does not directly address emotional regulation or expression, which are central to self-control.