As a Newborn,Mindy Was Fine When Her Parents Went Out

As a newborn,Mindy was fine when her parents went out and left her with a babysitter.As she approaches her first birthday,however,she has begun to cry when her parents leave.Though the sitter assures them that Mindy quiets down after they are gone,the separation process itself always involves tears.With regard to a developmental timetable,Mindy's behaviour is occurring

A) fairly late;most infants begin to fear separation around two to three months of age,because they have not yet developed adequate schemas for strangers versus nonstrangers.
B) right on time;this is the age at which a child has developed a strong attachment to the primary caregiver(s) .
C) extremely late;normally,separation anxiety occurs immediately after birth,since infants become attached to the mother in utero.
D) extremely early;most children do not show any distress at separation until at least age five.