Johnny, in one type of jump stop, you're allowed to land on one foot, then jump off that foot and land on two feet simultaneously. In that case, if the player lands "thump-thump", you have a traveling violation.

Maybe I am crazy, but who lands on one foot with the other in the air and then jumps off that one foot and lands on both feet. I am not sure I have ever seen that.

And if a player ends a dribble in the air - both feet off the ground - and lands thump-thump and (a) continues to try for a shot or pass or (b) stays stationary and pivots with the first foot to hit ground or (c) pivots with second foot to hit the ground.

The better players are pretty good at this on a drive. Ideally, they launch on a step/jump, gather the ball from the dribble, launch from the first foot to touch, and then land on both feet at the same time. This is the legal definition of a jump stop. In this case, if the final landing occurs with one foot then the other, it's a travel.

In this case, the first foot down is the pivot foot. Therefore, A is legal. B is legal. C is a travel.