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 6 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? O a. None is correct O b. 143.55,165.47 O c. 144.78, 159.11 O d. 146.01. 157.87 O e. 156.55.170.47 O f. 142.92.160.66