The current price of Bosto shares is €50. Over the coming year, there is a 40% probability that share returns will be 10%, a 40% probability that share returns will be 12.5%, and a 20% probability that share returns will be 30%. Bosto's expected return and standard deviation of returns for the coming year are closest to:
　　　Expected return　　　　Standard deviation

A.15.0%　　　　　　7.58%

B.17.5%　　　　　　5.75%

C.17.5%　　　　　　7.58%