Historical Rules · 23 July 2021
Rule 607.3
Official source text from the 23 July 2021 Rules release
If, within a pair of linked abilities, one ability refers to a single object as “the exiled card,” “a card exiled with [this card],” or a similar phrase, and the other ability has exiled multiple cards (usually because it was copied), the ability refers to each of the exiled cards. If that ability asks for any information about the exiled card, such as a characteristic or mana value, it gets multiple answers. If these answers are used to determine the value of a variable, the sum of the answers is used. If that ability performs any actions on “the” card, it performs that action on each exiled card. If that ability performs any actions on “a” card, the controller of the ability chooses which card is affected.