What is it called when an algorithm produces the same hash values for two different messages?

A.
Key cluster

B.
Collision

C.
Brute-force attack

D.
Birthday

Explanation:
Strong hashing algorithms should produce a small number or no
collisions. Two hashes created for two different messages should be different and
not the same value. If the same value is produced, then there can be patterns and
information that an attacker may use to uncover information. Hashing algorithms that
create longer digest values are less vulnerable to birthday attacks, which look for
collisions.