Answer:
The third riot was Astor place Riot
Explanation:
Astor place Riot happened on 10th May 1849 in which around 30 rioters were died and many injured. It occurred in Astor Opera House in Manhattan, New York. It was caused due to the dispute between two actors Edwin Forrest and William Charles Macready. The debate was that which of them is better in performing the roles from Shakespeare's dramas.