Bunuel

In the addition shown below A, B, C, and D are distinct digits. How many different values are possible for D ?
(A) 2
(B) 4
(C) 7
(D) 8
(E) 9
Attachment:
f247ec6fe2d36c608337f8763645addb01b26338.png
Key points :
1) All are distinct
2) All are single digit integers.
In any addition we always start from the right hand side.
Let us assume D =1 then A+B= 1 or 0 +1=1 or 1+0=1 so if A =1 then B=0 or Vice versa
let us take A=1 and B=0 and proceed, in the second column if D=1 then C has to be 0 this contradicts point 1 above , as all integers are supposed to be distinct. C and B both cannot be 0, hence D cannot be 1
Let us assume D=2 then A=0 and B=2 or vice versa , we can't have both as 1, as all are supposed to be distinct.
Put D=2 in second column then C=0, this again violates point 1 , hence D cannot be 2
Let us assume D=3 then first column A+B=1+2 or 2+1 let us take first case A=1 and B=2 , second column put d=3 then C=0 ,Third Column B + A= D so 2+1=3, Fourth Column B+C= B so 2+0=2, Fifth Column A+B=D so 1+2=3
So D can be 3 .
There is a pattern here in all those cases in which C=0 and is distinct ,we have a valid value for D.
So possible values of D are = 3,4,5,6,7,8 and 9, hence 7 values .
Ans C.
If the post helped please give Kudos.