For
option(A) : Refer above image 1,
For reversible operation, A and OUT should map to unique values of B.
Now, Refer above image 2,
We can see, mapping is not unique for B hence the operation is not reversible
For
option(B): Refer above image 3,
Each value of OUT has a unique value of A so we can say its uniquely mapped. Hence it's a reversible operation.
For
option(C) Refer above image 4,
For a reversible operation,
A and OUT should give unique values of B.
Refer above image 5,
We can find that the mapping of B with A and Out is not unique Hence the operation is not reversible.
for
option(D) Refer above image 6,
For a reversible operation,
A and OUT should give unique values of B.
Refer above image 7,
We can find that the mapping of B with A and Out is not unique Hence the operation is not reversible
On analyzing all the cases we can conclude that the Second operation is reversible, hence the correct option is (B)