Concept:Standard deviation measures how spread out the numbers are from the mean.Explanation:First, calculate the mean of the scores.Mean=54+5+6+7+8=530=6Next, find each score's deviation from the mean and square it.(4−6)2=(−2)2=4(5−6)2=(−1)2=1(6−6)2=02=0(7−6)2=12=1(8−6)2=22=4Sum of squared deviations =4+1+0+1+4=10Variance =number of scoressum of squared deviations=510=2Standard deviation =variance=2Answer:A. 2