In Cryptography, an initialization vector should be which of the following?

In Cryptography, an initialization vector should be which of the following?

• Unique and unpredicatable
• Repeatable and random
• Repeatable and unique
• Unique and predictable 

EXPLANATION

An initialization vector (IV) should be unique and unpredictable. To prevent an attack, an IV must not be repeated with a given key and should appear random.

SOURCE

https://en.wikipedia.org/wiki/Initialization_vector