Problem: a certain car dealership sells economy cars , luxury cars , and sport utility vehicles . the ratio of economy to luxury cars is 3 : 1 . the ratio of economy cars to sport utility vehicles is 4 : 3 . what is the ratio of luxury cars to sport utility vehicles ? 
Options: a ) 9 : 8 , b ) 4 : 9 , c ) 3 : 2 , d ) 2 : 3 , e ) 1 : 2
b