Until there is sufficient evidence otherwise,it must be assumed that ______.

A) both the null and alternative hypotheses are true
B) the alternative hypothesis is true
C) neither the null nor alternative hypotheses are true
D) the null hypothesis is true

The null hypothesis is the default assumption that we make in statistical testing. It is assumed to be true until we have sufficient evidence to reject it in favor of the alternative hypothesis. Therefore, until there is sufficient evidence otherwise, it must be assumed that the null hypothesis is true.