Problem: in a rectangular coordinate system , what is the area of a rhombus whose vertices have the coordinates ( 0 , 3.5 ) , ( 6 , 0 ) , ( 0 , - 3.5 ) , ( - 6 , 0 ) ? 
Options: a ) 42 , b ) 56 , c ) 88 , d ) 112 , e ) 116
a