Tagging Up in Baseball 1

During a baseball game a fly ball is hit toward left field along the third base line. The left fielder runs forward toward third base and catches the ball at point B on the spacetime diagram. The runner on third base tags up and starts off toward home base at point E on the spacetime diagram.

Answer the following questions:

1. At which spacetime point, labeled A through H, is the third base runner when the left fielder catches the ball at B in the umpire's frame of reference?
2. At which spacetime point, labeled A through H, is the third base runner when the left fielder catches the ball at B in the left fielder's frame of reference?
3. In the umpire's frame of reference, has the third base runner committed a foul? Explain, referring to the spacetime diagram.
4. In the left fielder's frame of reference, has the third base runner committed a foul? Explain, referring to the spacetime diagram.
5. If the umpire bases his judgment solely on the chronological order in which he actually sees the ball being caught and the runner leaving third base, will he call a foul? Explain, referring to the spacetime diagram.