A runner retains the right to unoccupied base until which of the following occurs?

A runner retains the right to an unoccupied base until he is put out. This means that as long as the runner has not been put out by the opposing team through actions such as tagging or force plays, he is allowed to remain on the base he has reached safely without the threat of losing that position. This concept is crucial for understanding base running and the status of runners throughout a play in baseball.

The other options describe situations that do not impact the runner's right to an unoccupied base in the same manner. For instance, touching the next base while it is unoccupied does not negate the rightful claim to the previous base unless a play is made to put the runner out. Similarly, waiting for a following runner to advance or being tagged does not relate directly to retaining the right to an unoccupied base, as those actions depend on distinct game circumstances. Hence, the runner's right to an unoccupied base is primarily governed by whether he has been put out.