[tex]Least\ common\ denominator:\\\\\frac{7}{9}\ \ \ \frac{5}{12}\ \ we\ need\ to\ find\ number\ which\ can\ be\ divided\ by\ 12\ and\ 9\\\\\frac{7\cdot4}{9\cdot4}\ \ \ \frac{5\cdot3}{12\cdot3}\\\\\frac{28}{36}\ \ \ \frac{15}{36}\\\\Answer\ A. [/tex]