Based on the confidence interval for these data, and assuming a null hypothesis that there is no mean difference between these groups in the population, what can we infer about the decision for a null hypothesis significance test at a .05 and at a .01 level of significance for a two-tailed test?

a. The decision would have been to reject the null hypothesis at a .05 but not at a .01 level of significance.

b. The decision would have been to reject the null hypothesis at a .01 but not at a .05 level of significance.

c. The decision would have been to fail to reject the null hypothesis at a .05 and at a .01 level of significance.

d. The decision would have been to reject the null hypothesis at a .05 and at a .01 level of significance.