An auditor for a hardware store chain wished to compare the efficiency of two different auditing techniques. To do this he selected a sample of nine store accounts and applied auditing techniques A and B to each of the nine accounts selected. The number of errors found in each of techniques A and B is listed in the table below: Errors in A Errors in B 45 31 48 37 46 39 48 37 52 54 50 45 49 49 40 41 45 50 Select a 90% confidence interval for the true mean difference in the two techniques. V a) O [3.050, 5.838] cro b) O [-4.183, 4.183] c) O [2.584, 6.304] d) O [2.195, 6.693] Micro e) [0.261, 8.627]