In order to get the answer to this question you must multiply the numerators then multiply the denominators and reduce if needed.
[tex]\frac{1}{5} \times\frac{6}{7}[/tex]
[tex]1\times6=6[/tex]
[tex]5\times7=35[/tex]
[tex]=\frac{6}{35}[/tex]
Therefore your answer is option C "6/35."
Hope this helps.
