Children's fitness is assessed by finding the distance, in meters, that they can run in 6 minutes. Overall, this distance varies fairly normally, with mean 835 and standard deviation 111. The following distances are all below average; find their z-scores and characterize each as showing fitness to be exceptionally poor, borderline, or unexceptional, if we decide to call fitness "exceptionally poor" when distance run is considerably less than 2 standard deviations below the mean, "borderline" if it is close to 2 standard deviations below the mean, and "unexceptional" otherwise.
a. 600 meters
b. 354 meters
c. 742 meters
d. 623 meters