The run definitely counts in B. An appeal play or a "returning to tag" play is not a force. It is a "time play".
Here is the entire text of rule 5.08 a.
"(a) One run shall be scored each time a runner legally advances to and touches first, second, third and home base before three men are put out to end the inning.
EXCEPTION: A run is not scored if the runner advances to home base during a play in which the third out is made (1) by the batter-runner before he touches first base; (2) by any runner being forced out; or (3) by a preceding runner who is declared out because he failed to touch one of the bases."
Post above clarifies all related situations, using an actual MLB play that is very similar. Remember, returning to a base is not a force play.