Answer:
D. The small p value and the small effect size suggest that the observed difference between the drug placebo groups are likely to be due to sampling error. This study should be replicated with a larger sample size.
Explanation:
The p value is determined for any test before making a conclusion. If the p-value is smaller than critical value then we reject the null hypothesis which means that drug is not effective for the reducing depression. A very small p-value usually lesser than 0.05 indicates strong evidence against the null hypothesis.