Calculate the sum of the following mixed fractions.  $\textasciitilde$  $1\frac{1}{3} + 2\frac{9}{12} + 3\frac{3}{5} + 4\frac{1}{4} + 5\frac{4}{6} + 6\frac{10}{25}$ =~\uline{~~~~~~~~~~}~  $\textasciitilde$ 
选项为:A:$$18$$  B:$$21$$  C:21$\frac{7}{12}$  D:$$24$$  E:$$27$$  请回答其中一个选项.