How do Burn It and weapon siphon interact?

A particularly crafty goblin alchemist has decided to furnish their +2 greater striking Dogslicer (item level 12) with a weapon siphon (item level 1), into which they insert a bottle of greater alchemist's fire (item level 11). The goblin activates the weapon siphon and lands a strike with the Dogslicer. They have the Burn It ancestry feat. Which of the following applies?

a) The Dogslicer, a level 12 item, inherits the alchemical trait from its attachment and deals the fire damage, increasing the 1d4 fire damage dealt by +3.

b) The damage is dealt by the alchemist's fire, a level 11 item, increasing the 1d4 fire damage dealt by +2.

c) The 1d4 fire damage is dealt by the attachment, which remains a lvl 1 item, increasing the 1d4 fire damage by +1.

d) There is no damage bonus from Burn It, as the weapon itself is dealing the additional damage while remaining non-alchemical.

e) There is another issue that I overlooked.

If c) or d) is the case, would it be different for an alchemical gauntlet?