A surrogate key may be appropriate when the available candidate keys would produce a lot of data duplication when representing relationships and they would be prone to typographical errors.
Answer: Option 3
Explanation:
In a fact table, sometimes there may be a few keys that would repeat the data over and over again. Thus to avoid this repetition or duplication, surrogate keys may be used instead of other candidate keys.
In most instances, surrogate keys are nothing else but the integer keys. They are mostly used as primary keys instead of using a natural or a real key in its place. The function of a surrogate key is to serve as a numeric identifier.