Which of the Following Statements About Schum Et Al

Which of the following statements about Schum et al.'s (2002) study on potty training is FALSE?

A) It found that boys achieve an interest in using the toilet and staying dry through the night an average of two months earlier than girls.
B) It found that at least half of girls showed an interest in using the toilet by 24 months of age.
C) It noted that the average age of daytime dryness was about 24 months during the 1950s.
D) It showed that many of the African American toddlers in their sample began potty training before 15 months.