Which is the best explanation for why the subjunctive mood is used?

Question

In some cases, you need to express a wish or desire
Sometimes you are making a request or asking something
There are times when you do not know how a situation will turn out
Often, you need to make a definitive statement

Answer 1

The best explanation for why the subjunctive mood is used is: There are times when you do not know how a situation will turn out.

The subjunctive mood often expresses uncertainty, hypotheticals, wishes, desires, or conditions contrary to fact, which aligns with situations where the outcome is uncertain or not guaranteed.