Katherine Webb -- The Million Dollar PLAYBOY Question

It's the question millions of gentlemen ... and Brent Musburger ... have been dying to know -- WILL KATHERINE WEBB TAKE IT OFF FOR PLAYBOY?!?!??

Miss Alabama USA -- more famously known as AJ McCarron's super hot GF -- arrived at LAX yesterday when one of the photogs finally posed the question ... and her answer is interesting.

It's clear the decision to do it would upset some very important people in her life ... but IF they were ever to come around, you think she would too?