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Answer (A) is correct . Since three standard deviations incorporate over 99% of all observations, and two standard deviations incorporate over 95% of observations, less than 5% will not be included within two standard deviations, and this is divided between both ends of the normal curve. Therefore, less than 2.5% of the observations will be in the negative portion of the curve.

Answer (B) is incorrect because The 5% of observations not covered within two standard deviations are divided between the two tails of the curve.
Answer (C) is incorrect because The 5% of observations not covered within two standard deviations are divided between the two tails of the curve.
Answer (D) is incorrect because The 5% of observations not covered within two standard deviations are divided between the two tails of the curve.