Achondroplasia, a skeletal dysplasia, causes the condition known as dwarfism, in which subjects have smaller stature (height) than persons without the condition. The following results are based on a random sample of 292 newborns diagnosed with achondroplasia. The boxplots and summary statistics below give characteristics of the birthweight distributions separately for the male and female newborns. N = 164; mean = 3.3 kg standard deviation = .6kg

The mother of a newborn boy with achondroplasia wants to know her child's weight percentile at birth, so that his growth can be tracked over time as he ages. The newborn boy weighs 3.9 kg. Based on the information given above, and again assuming that the distribution of weights in newborn males with achondroplasia is (approximately) normal, to what percentile in the weight distribution for males does 3.9 kg correspond?

a. 16th

b. 32nd

c. 68th

d. 84th