In a fabric manufacturing factory, the quality control process using control charts from SPC. In an hour there are a total of 5 samples are taken each having 4 observations regarding the thickness of fabric in measured in millimeters. In a particular hour, the sample means (X-bar) are noted to be: 156.46, 199.62, 189.31, 102.22, and112.09 respectively. In the same sample, the corresponding ranges are: 11.97.12.17, 13.94, 11.86, and 11.83 respectively. ?What are the lower and upper control limits for the X-bar chart 170.47.156.55 a O 190.72.145.40 b c 160.96,142.92.c None is correct d O 159.11.144.77 e 165.47.143.55fe