Final answer:
Children in elementary school develop their 'Theory of mind' which helps them understand that others have their own thoughts and feelings, aiding in emotional regulation.
Step-by-step explanation:
During the elementary school years, children go through significant cognitive development, enabling them to better understand and regulate emotions. The correct answer to the question is a) Theory of mind (TOM). This concept refers to the understanding that others have thoughts, feelings, and beliefs different from one's own. By developing theory of mind, kids learn to interpret and respond to others' emotional states, which helps in regulating their own emotional responses. For example, they can appreciate that a sibling might feel angry because of a shared understanding that the sibling has their own unique perspective and experiences.
It's also worth noting that this period is characterized by an expansion of cognitive skills, where thought processes become more organized and logical when dealing with concrete information. Cognitive development allows children to grasp concepts such as cause and effect, time, and planning.