Stefani is ordering fertilizer for her garden. A local garden supply store sells fertilizer by the yard (that really means cubic yard, but that is what they call it).For every yard she orders there is a $\textbackslash$$15charge and ,in addition ,there is a $\textbackslash$$40 delivery charge. ( Total Cost =~$\textbackslash$$15(yard)+~$\textbackslash$$40.)  $\textasciitilde$  If the average order is 4.3 yards with standard deviation of 2.9 yards, what is the mean and standard deviation of the Total Cost of a typical order? 
选项为:A:mean = $\textbackslash$$4.30; standard deviation =~$\textbackslash$$2.90  B:mean = $\textbackslash$$64.50; standard deviation = $\textbackslash$$43.50  C:mean = $\textbackslash$$105.50; standard deviation =~$\textbackslash$$43.50  D:mean = $\textbackslash$$105.50; standard deviation = $\textbackslash$$83.50  E:Cannot be determined because each order may not be independent~  请回答其中一个选项.