Final answer:
The close emotional bond that infants form with parents, caregivers, or others is called emotional attachment, and it is a major social milestone of infancy. Researchers have identified different types of attachment styles, with secure attachment being the most common and considered the healthiest. option c.
Step-by-step explanation:
The close emotional bond that infants form with parents, caregivers, or others is called emotional attachment. This attachment is a long-standing connection or bond with others, and it is a major social milestone of infancy. Researchers have identified different types of attachment styles, with secure attachment being the most common and considered the healthiest. In a secure attachment, the infant prefers their parent over a stranger and seeks out their parent for safety and comfort.