In Histogram Matching or Specification, z = G-1[T(r)], r and z are gray level of input and output image and T & G are transformations, to confirm the single value and monotonous of G-1 what of the following is/are required?

In Histogram Matching or Specification, z = G-1[T(r)], r and z are gr

1.	In Histogram Matching or Specification, z = G-1[T(r)], r and z are gray level of input and output image and T & G are transformations, to confirm the single value and monotonous of G-1 what of the following is/are required?
A.	G must be strictly monotonic
B.	G must be strictly decreasing
C.	All of the mentioned
D.	None of the mentioned
Answer» B. G must be strictly decreasing