Problem: in a rectangular coordinate system , what is the area of a quadrilateral whose vertices have the coordinates ( 4 , - 3 ) , ( 4 , 7 ) , ( 12 , 2 ) , ( 12 , - 7 ) ? 
Options: ['a ) 64', 'b ) 68', 'c ) 72', 'd ) 76', 'e ) 80']
d