Ranger - weapon element and flame arrow skill

Flame arrow skill description states that it gives fire element to arrows. I'm trying to figure it out and came up with some possible answers; which ones are correct?

What happens when my bow has a water element?

• It's going to decrease the damage of flame arrow.
• Flame arrow overrides weapon element, making it always fire.
• If the weapon element is overridden, it still applies an element bonus even if it's other than fire.
• Fire element on the weapon increases flame arrow damage.
• It does nothing, and element bonuses are calculated separately: A water mob attacked with an electric bow will receive extra damage, but the flame arrow will be weaker.