For 24, I believe C is correct. The ball carrier is not airborne, so the progress spot is the location of the ball when it is declared dead (between the goal lines, even if the ball is outside the sideline).
Boy, this one is really something, one would think very basic, but .....
? In order to go with c what we're really offering is a "LTG line extended" concept. That's something I've never heard discussed.
When I was a LJ many moons ago, we always spotted the ball where it crossed the sideline on this play.
Suppose the runner is near the right sideline at the 50 yard line 1 yard short of the LTG at the 49. He is facing directly at the sideline, with his shoulders parallel to the sideline. Realizing he is falling straight on his face and cannot reach the LTG, so as he falls he reaches the ball out with his left hand (this dude has a huge wingspan) and then first contacts the ground with his right hand. When that happens the ball is 2 yards OB (he's taller than 6 feet) but it reached the "line to gain extended". Remember since he was facing the sideline, the ball crossed the sideline at the 50.
So when the ball becomes dead (when his right hand touched OB), the ball is 6 feet OB, and 3 feet downfield still OB.
Are we now saying this is a 1st down, because, unless I've totally lost it, it was not last year, nor for as many as I can remember.
Another play, runner is running at an angle toward the sideline and realizes his next step will be on the sideline. So he extends the ball out over the sideline but enough forward to have it's tip beyond the LTG extended OB (again a concept I've never heard of), then he steps on the sideline. What then?
What am I missing?