Problem: the volumes of two cones are in the ratio 1 : 12 and the radii of the cones are in the ratio of 1 : 3 . what is the ratio of their heights ? 
Options: ['a ) a ) 3 : 4', 'b ) b ) 2 : 7', 'c ) c ) 2 : 2', 'd ) d ) 2 : 1', 'e ) e ) 2 : 9']
a