NFHS Clock Status

[Warrenkicker]

Where the ball became dead in B's possession is going to control if the clock starts on the ready or the snap. If B went OOB to end the down then the clock starts on the snap. If B was tackled in-bounds then the clock starts on the ready.

By the way, the clock stopped because of the foul, not because B had possession of the ball. Either would stop the clock but the foul takes precedence over the possession. If the penalty is declined then the fact that B gets a new series controls the clock.