Your roommate ate your leftover pizza. You want to know: "Someone gave him permission." Which question has the preposition in the correct position for everyday English?

The correct answer is "Who did you get permission from?"

In everyday spoken English, the preposition goes at the end of the question: Who did you get permission from?

"From who did you get permission?" is close to the formal pattern, but formal English requires "whom" (From whom did you get permission?). The other two options place the preposition in impossible positions — it cannot go between the auxiliary and the verb or between the question word and the auxiliary.