An x-bar and R chart was prepared for an operation using 20 samples with five pieces in each sample. X-barbar was found to be 33.6 and R-bar was 6.20. During production, a sample of five was taken and the pieces measured 36, 43, 37, 25, and 38. At the time this sample was taken:

a. both the average and range were within control limits. 

b. neither the average nor range were within control limits. 

c. only the average was outside control limits. 

d. only the range was outside control limits.