What type of hash function is used, when there is a variable number of items to be hashed, such as the many state changes in a block?

A)  Either
B)  Simple Hash
C)  Complex hash
D)  Tree-structured Hash

Correct Answer :   Tree-structured Hash


Explanation : In the fields of cryptography and computing science, Hash trees, also known as Merkle trees, are a sort of data structure that stores a tree of summary information about a bigger piece of data, such as a file, and is used to validate its contents. Hash trees are a subset of hash lists, which are themselves subsets of hashing.