[tex] \frac{1}{6}+ \frac{3}{4}+ \frac{2}{3}= \\
\\ \frac{1}{6}+ \frac{3}{4}= \\
\\ \frac{1*2}{6*2}= \frac{2}{12} \\
\\ \frac{3*3}{4*3}= \frac{9}{12} \\
\\ \frac{2}{12}+ \frac{9}{12}= \frac{11}{12} \\
\\ \frac{11}{12}+ \frac{2}{3}= \\
\\ \frac{11*1}{12*1}= \frac{11}{12} \\
\\ \frac{2*4}{3*4}= \frac{8}{12} \\
\\ \frac{11}{12}+ \frac{8}{12}= \frac{19}{12} \\
\\ \frac{19}{12}=1 \frac{7}{12} \\
\\ Answer:\boxed{D.1 \frac{7}{12}} \\ [/tex]