The most common incidence of interference occurs when a member of the offensive team physically hinders the defensive team, decreasing its chances to make an out or increasing the chance that a baserunner will advance. Whenever this offensive interference occurs, the ball becomes dead. If the interference was committed by a batter or a baserunner, that player is called out and all other runners must return to the bases they occupied at the time of the interference. If interference is committed by a runner with the obvious intent of preventing a double play, the batter-runner will be called out in addition to the runner who committed the interference. If interference is committed by the batter-runner before he or she reaches first base with the possible intent of preventing a double play, the runner closest to scoring is called out in addition to the batter-runner. If interference is committed by a retired runner or by some other member of the offensive team, the runner who is most likely to have been put out will be called out.

What's the best answer to this question: is the ball dead when it hits a runner?
yes