118.12

Some spells, activated abilities, and triggered abilities read, “[Do something]. If [a player] [does, doesn’t, or can’t], [effect].” Or “[A player] may [do something]. If [that player] [does, doesn’t, or can’t], [effect].” The action [do something] is a cost, paid when the spell or ability resolves. The “If [a player] [does, doesn’t, or can’t]” clause checks whether the player chose to pay an optional cost or started to pay a mandatory cost, regardless of what events actually occurred.