The annual snowfall in town has mean of 31 inches and standard deviation of 11 inches. Last year there were 67 inches of snow. How many standard deviations from mean is that?
a) 3.27 standard deviations above the mean
b) 0.30 standard deviations below the mean
c) 3.27 standard deviations below the mean
d) 0.30 standard deviations above the mean