If I play as Chaos, in my turn, I play a attachment card to my opponent's unit, then he play Iron Discipline to response, and I can't pay the 4 more resources, what will happen?

Situation 1: I play Effulgent Boils(Attach to a target unit. Corrupt that unit. Attached unit cannot be restored.) on his unit, then he play Iron Discipline on that unit to response, and I can't pay the 4 more resources

A)I can't play Effulgent Boils on his unit, and that attachment card will be discard.

B)Nothing happen, because play an attachment card on a unit is not an action.

C)others(please explain)

Situation 2: I play Necrotic Spasm(Attach to a target unit. ACTION: At the beginning of its controller's turn, attached unit takes 1 uncancellable damage.) on his unit, then he play Iron Discipline on that unit to response, and I can't pay the 4 more resources

A)I can't play Necrotic Spasm on his unit, and that attachment card will be discard.

B)Nothing happen, because play an attachment card on a unit is not an action.

C)Nothing happen this turn, because play an attachment card on a unit is not an action, but if he play another Iron Discipline at the beginning of his turn, I need to pay 4 more resource to deal 1 uncancellable damage.

D)Nothing happen on this turn or his turn, because the phase 0 Beginning of Turn will resolve first, then players can take his action after.

E)others(please explain)

Playing a support is considered an action and opens an action window. Your opponent can then play a card in response. If Iron Discipline is played in response to a Chaos attachment and you do not have the resources to get around it, your Chaos attachment can not be played and will fizzle.

A pretty minor distinction on Doc9's post, but the attachment is "cancelled" and goes to your discard pile. If you are trying to target a card like King Kazador, which always costs 3 extra resources to target, then you can't even attempt to play the attachment unless you have the resources.

Wow, Iron Discipline is a real doozy of a card.