James has a desk job and would like to become more fit, so he purchases a tread walker and a standing desk which will allow him to walk at a slow pace as he works. However, he is concerned that standing and walking while working may cause his productivity to decline. After working this way for 6 months he takes a simple random sample of 15 days. He records how long he walked that day in hours) as recorded by his fitness watch as well as his billable hours for that day as recorded by a work app on his computer. Regression Analysis: Billable hours versus Walk time Predictor Constant Walk time Coef 7.785 -0.245 SE Coef 0.542 0.205 T 14.363 -1.195 0.000 0.127 Assuming that all conditions for inference are met, which of the following is a 95 percent confidence interval for the average change in the number of billable hours for each increase of 1 hour spent walking? (A) -0.245 + 1.960(0.205) (B) -0.245 + 2.131(0.205) (C) -0.245 + 2.160(0.205) (D) 7.785 + 1.960(0.542) (E) 7.785 + 2.160(0.542)