I also agree with this being a 1st and 10 scenario.
The rule states that, when the :40 play clock is being used, the ball is "ready for play" when it has been placed on the ground and the covering official has moved to their position -- i.e., if the U is standing over the ball, it is not yet ready for play.
If B (or A, for that matter) calls a timeout to preserve time as soon as the previous play ends, then the ball has not been placed at the in-bounds spot and made ready for play until the RFP after the timeout. Any penalty prior to that point will cause the chains to reset along with the down marker and it remains 1st and 10.
If, on the other hand, after the play resulting in a first down, the ball is placed down, the U moves away, A lines up and doesn't like the play call/defensive coverage/whatnot and then calls timeout, the ball has been made ready for play. Any penalty prior to the RFP after the timeout will result in 1/15 (or 25 or whatever).
Regardless of the outcome, I still do not understand the animosity from Al and NV over posting a question to generate a conversation. I don't particularly like being called stupid for trying to spark discussion.