Another NCAA question

[dash_riprock]

R2 is attempting to score on a base hit. As R2 approaches home plate, the throw from F9 is up the third base line causing F2 to move up the baseline in order to catch the ball. As the ball is approximately 10 feet from F2 and he is preparing to glove the ball, he collides with R2 and both are knocked to the ground. F1, backing up the play, picks up the ball and tags R2 before he can touch home base.

a. This is obstruction by F2 and R1 is awarded home.

b. This is a legal play and R1 is called out on the tag by F1 and is ejected if the slide is deemed flagrant.

c.This is interference by R1 and he is called out immediately.

d.This is a legal play and R2 is called out on the tag by F1.

N.B. D is the only answer that correctly identifies the baserunner. I don't know if it's 3 typos or a clue.