Jake,a Two-Year-Old Toddler,is Left with a Babysitter While His Parents

Jake,a two-year-old toddler,is left with a babysitter while his parents go out to dinner.Surprisingly,he isn't particularly upset when they leave though he hangs onto his teddy bear.In addition to the fact that Jake has learned that his parents don't cease to exist when they are out of his sight,Jake's response is most likely a result of:

A) object permanence.
B) his developing emotion regulation skills.
C) egocentrism.
D) the process of accommodation.