Rolling a die to see if you know something... well. Yeah. With this variant, you never roll a Knowledge skill check.
Take 10: With this variant, you always 'take 10' on Knowledge checks (even under duress). Your Knowledge skill check result is equal to 10 + any permanent modifiers. Do not include temporary bonuses, such as those that result from fox's cunning, as the point of this variant is to move Knowledge away from being an active, in-the-moment thing and toward representing your character's static arsenal of information. Even characters untrained in Knowledge take 10 with this variant; if this would boost their result over 10, treat their result as a 10.
Lore Master: This variant decreases the utility of abilities like lore master and jack-of-all-trades, which let you take 10 on Knowledge skill checks at any time. A class feature or feat which allows a character to take 10 on Knowledge skill checks—now the default state of affairs—instead gives an untyped +2 bonus on said checks.