The H.C.F. of the fractions \[\frac{8}{21},\frac{12}{35},\] and \[\frac{32}{7}\] is

• A.  \[\frac{4}{105}\]                               
• B.  \[\frac{192}{7}\]
• C.  \[\frac{4}{7}\]                                   
• D.  \[\frac{5}{109}\]