Every distinct wording since 2010, newest first.
July 12, 2019 · Core Set 2020
A triggered ability is targeted if it identifies something it will affect by using the phrase “target [something],” where the “something” is a phrase that describes an object and/or player. The target(s) are chosen as the ability is put on the stack; see rule 603.3d.
February 1, 2010 · Worldwake
A player may activate a mana ability whenever he or she has priority, whenever he or she is casting a spell or activating an ability that requires a mana payment, or whenever a rule or effect asks for a mana payment (even in the middle of casting or resolving a spell or activating or resolving an ability).