In the Abecedarian Project (Ramey & Campbell), Statistically Significant Differences

In the Abecedarian Project (Ramey & Campbell) , statistically significant differences were found between children in the experimental group and children in the control group. Which of the following is true?

A) These differences were likely due to chance.
B) These differences will likely be found again if the study is repeated.
C) The differences indicate a cause and effect relationship between the independent and dependent variables.
D) The differences must have been due to the intervention.