A Random Sample of 16 Companies Was Selected and Asked $\pm$

Multiple Choice

A random sample of 16 companies was selected and asked for their annual dividend rate in three different industries: utilities, banking, and insurance. The ANOVA comparing the mean annual dividend rate among three industries rejected the null hypothesis. The Mean Square Error (MSE) was 3.36. The following table summarized the results:
When comparing the mean annual dividend rate for companies in the utilities and insurance industries, the following 95% confidence interval can be constructed:

A) 5.78 $\pm$ 2.160 * 2.40
B) 5.78 $\pm$ 2.120 * 2.40
C) 5.78 $\pm$ 2.160 * 1.11
D) 5.78 $\pm$ 2.120 * 1.11