and x and R chart was prepared for an operation using twenty samples with five pieces in sample. x was found to be 33.6 and R(with bar) was 6.2. During production a sample of five was taken and the pieces measured 36, 43, 37, 25, and 38. At the time the sample was taken

a) Both the average and range were within control limits

b) Only the average was outside control limits

c) Only the range was outside control limits

d) Neither the average nor range were within control limits