question_answer

Find the missing number. \[\frac{3}{4}\left( 1+\frac{1}{3} \right)\left( 1+\frac{2}{3} \right)\left( 1-\frac{2}{5} \right)\left( 1+\frac{6}{7} \right)\left( 1-\frac{12}{13} \right)=?\]

A)  \[\frac{1}{5}\]                       

B)  \[\frac{1}{6}\]           

C)  \[\frac{1}{7}\]           

D)       \[\frac{1}{13}\]