A Researcher's Theory That Teaching the Alphabet Backwards Shortens the Time

Multiple Choice

A researcher's theory that teaching the alphabet backwards shortens the time to learn letters was not found to be statistically significant.It could be that

A) this method of teaching letters is not helpful.
B) the method of teaching letters is helpful but there were problems with the design of the study.
C) the method of teaching letters is helpful but the design lacked the power to reject the false null hypothesis.
D) All of these are true.
E) None of these is true.