Consider an additive noise channel Y = X+Z, where the signal X ~ X+Z, where the signal X ~ N(0,σ^2) and the noise Z has zero mean and variance v^2. Assume X and Z are independent. Find a distribution of Z that maximizes the minimum MSE of estimating X given Y, i.e., the distribution of the worst noise Z that has the given mean and variance. Justify your answer.