If the sum and difference of two numbers are 20 and 8 respectively, then the difference of their squares is 


(a) 
12 
(b) 
28 
(c) 
160 
(d) 
180 
If the sum and difference of two numbers are 20 and 8 respectively, then the difference of their squares is 


(a) 
12 
(b) 
28 
(c) 
160 
(d) 
180 