A certain game uses a set of cards containing odd numbers. There are one 1, three 3s, two 5s, one 7, and three 9s. The mean value of this deck is 5.4, with a standard deviation of 2.8. If someone purchased three more decks of these cards and combined~them into single large deck, what would the new mean and standard deviation be? 
选项为:A:Mean = 5.4; standard deviation = 2.8  B:Mean = 5.4; standard deviation = 2.95  C:Mean = 16.2; standard deviation = 2.90  D:Mean = 16.2; standard deviation = 8.4  E:Mean = 21.6standard deviation = 11.2  请回答其中一个选项.