Rule 355.5.b

This does not include making choices for Triggered Abilities of permanents, or Delayed or Reflexive Triggers generated by the item being finalized, even if those abilities trigger when the chain item is played. Example: A unit with a triggered ability that says "When I'm played, kill a unit" does not require you to choose a target as it's played. The target will be chosen when the ability triggers. Example: Targon’s Peak reads “When you conquer here, ready up to 2 runes at the end of this turn.” Readying up to 2 runes at the end of the turn is the effect of a delayed trigger; any choices involved are not made when finalizing the conquer effect but when finalizing the resulting delayed trigger at the end of the turn. See rule 382. Triggered Abilities for more information.