You have been asked by a German client to recommend an asset allocation among four frontier markets: Nigeria, Pakistan, Ukraine, and Vietnam. After conducting an empirical investigation, you have concluded that Euro- denominated returns among these four countries are es- sentially uncorrelated. Sample mean returns (%/annum) and volatilities (annual standard deviations of returns) are shown below: Mean Volatility Nigeria 32% 18% Pakistan 10% 21% Ukraine -8% 16% Vietnam 13% 22% What is your estimate of minimum volatility achievable in a portfolio from these countries