arrogance or ignorance which is worse?

Arrogance is wilful ignorance. That's worse than you're plain old average ignorance.

Arrogance, it is a chronic form of ignorance.
It is rarely treatable compared to simple ignorance.

in it's truest sense ignorance means uninformed, so arrogance for sure is worse.

A bad combination of both.

Ignorance. People tend to know when they're arrogant, or at least have some clue. But idiots who know nothing about a topic will still spout off as if they had anything intelligent to offer.

Arrogance, if a person is ignorant there is a chance to give them information they were missing. Arrogance they have to figure out on their own.

That's kind of a toss-up; I'd say a mix of both is way worse than either on its own.

Arrogance, by far. It is often chosen ignorance.