which one is not self complemetry code

Question

Answer 1

Self complementing code is a code wherein sum of weights is 9. Except for D, all other options have sum of weights=9

Answer 2

if we find 9's complement of the no 

and also find the 1's complement of the no according to given weightage then if it will stisfied then given weightage is self complemantary code.

9's complement 2 is 7   for this if we represent 2 by weightage and take 1's complememnt then the no is selfcomplememntry code

CODE	representation of 2	representation of 7 by taking its 1's complement according to given codes	result
2421	0010	1101	yes
5211	0011	1100	yes
84-2-1	0110	1001	yes
641-3	here 2 can't be representation	1010	no

Answer 3

d) 641-3

Comments

answer is d as sum of weights here is not 9 here