When Marcia and Stanley drop their 12-month-old son off at d…

When Marcia and Stanley drop their 12-month-old son off at day care, he does not seem at all disturbed that they are leaving. He prefers to play by himself or with other kids. When they show up later to pick him up, he crawls away from them. Based on this, the toddler is most likely demonstrating a(n) __________ attachment to his parents.