Which Class Had the Smallest Standard Deviation

Multiple Choice

Which class had the smallest standard deviation?

A) Class 3,because the shape is symmetric and unimodal.
B) Class 1,because the shape is fairly symmetric and uniform.
C) Class 3,because the shape has the highest number of students.
D) Class 2,because the shape is skewed.
E) None,because the classes had the same standard deviation.