If the sample size is 15 and the test is being carried out at the 5% level of significance, the null hypothesis will be rejected if: a) The test statistic is less than -1.96 or greater than 1.96 b) The p-value is greater than 0.05 c) The test statistic is between -1.96 and 1.96 d) The p-value is less than 0.05