The Stock Market of Country a Has an Expected Return

Essay

The stock market of country A has an expected return of 5%, and standard deviation of expected return of 8%. The stock market of country B has an expected return of 15% and standard deviation of expected return of 10%.
Is it reasonable to conclude that your portfolio is on the efficient frontier? If not, then prove your point by finding just one portfolio weighting between A and B that offers more return with less risk. If you think it is on the efficient frontier, why do you think this? No points for guessing.