When does the ball become dead due to obstruction?

In baseball, obstruction is a situation where a defensive player impedes the progress of a runner, which is a significant play that can affect the game's outcome. The authorities recognize that different scenarios can lead to a ball being ruled dead due to obstruction.

When you look at the circumstances under which the ball becomes dead, it clearly demonstrates that obstruction is not limited to scenarios involving only runners. An obstruction call creates a scenario where the play stops immediately to address the interference caused by a defensive player, preserving the integrity of the game and ensuring fairness.

While changing pitchers or awarding an intentional base on balls are part of the game's natural flow, they don't cause the ball to be dead in the same direct way as an obstruction incident involving a runner does. However, from a broader perspective, there can be interpretations depending on game situations, which could lead to similar outcomes as if they were obstruction-related calls. Yet, the initial and fundamental aspect of obstruction strictly pertains to the action where a runner is interfered with.

Hence, considering all contexts, the correct answer encapsulates the various scenarios where the ball can be ruled dead, effectively asserting that any situation fitting the definition of obstruction triggers the same rule activation as seen in intentional base awards or pitcher substitutions.