Problem: the points a ( 0 , 0 ) , b ( 0 , 4 a - 5 ) and c ( 2 a + 1 , 2 a + 4 ) form a triangle . if angle abc = 90 , what is the area of triangle abc ? 
Options: a ) 80 , b ) 75 , c ) 70 , d ) 60 , e ) 65
e