Which of the Following Does Not Obey the Mean-Variance Rule

Which of the following does not obey the mean-variance rule?

A) Project X will be preferred to project Y if the standard deviation on X and Y is the same, but the expected return on Y is lower.
B) Project X will be preferred to project Y if the expected return on X exceeds that of Y and the variance is equal to or less than that of Y.
C) Project X will be preferred to project Y if the expected return on X and Y is the same, but Y has a higher standard deviation.
D) Project X will be preferred to project Y if the variance of X is higher than Y and the expected return is lower than Y.