117.12. Some spells, activated abilities, and triggered abilities read, “[Do something]. If [a player]
[does or doesn’t], [effect].” or “[A player] may [do something]. If [that player] [does or doesn’t],
[effect].” The action [do something] is a cost, paid when the spell or ability resolves. The “If [a
player] [does or doesn’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.