Damage prevention

[VsTheWorld]

This came up at a wacky draft I did last week. I control Benevolent Ancestor, my opponent attacks with Looter il-Kor and a Mulldrifter. I activate Ancestor's ability to prevent the next 1 damage that would be dealt to me. Now the question: do I choose which of the 3 damage to prevent? Obviously I was trying to prevent the 1 dealt by Looter to deny my opponent the card draw, and we came to a consensus that I was in fact able to choose the damage, but I'd just like some sort of actual ruling on this.

[Pinder]

419.7b Some prevention effects generated by the resolution of a spell or ability refer to a specific amount of damage-for example, "Prevent the next 3 damage that would be dealt to target creature or player this turn." These work like shields. Each 1 damage that would be dealt to the "shielded" creature or player is prevented. Preventing 1 damage reduces the remaining shield by 1. If damage would be dealt to the shielded creature or player by two or more applicable sources at the same time, the player or the controller of the creature chooses which damage the shield prevents first. Once the shield has been reduced to 0, any remaining damage is dealt normally. Such effects count only the amount of damage; the number of events or sources dealing it doesn't matter.


There you go.