By around what age does a child’s theory of mind allow them to understand that people think differently and have different preferences?

The correct answer is B. 4 years old.

By around 4 years old, children typically develop a theory of mind, which means they can understand that others have different thoughts, beliefs, and preferences than their own. This cognitive development allows them to recognize that people can have different perspectives and that these perspectives can influence behavior. If you have more questions or need further clarification, feel free to ask!