A mother is concerned because her 18-month-old toddler has 12 teeth. She is wondering if this is normal for a child of this age. Which is the best response by the nurse? 1) How many teeth did you have at this age? 2) This is a normal number of teeth for an 18 month old. 3) Normally, by age 2 1/2 years, 16 deciduous teeth are expected. 4) All 20 deciduous teeth are expected to erupt by age 4 years.