Data collected by child development scientists produced the following 90% confidence interval for the average age (in months) at which children say their first word: 10.4<<13.8.

A. We are 90% confidence, that the mean age at which children say their first word is between 10.4 and 13.8 months. B. 90% of children will say their first word when they are between 10.4 and 13.8 months old. C. 90% of the children in this sample said their first word when they were between 10.4 and 13.8 months old. D. We are 90% confident that the average age at which children in this sample said their first word was between 10.4 and 13.8 months.