Answer:
Option B.
Explanation:
Workers at the rally admitted planting a bomb, is the right answer.
The Haymarket Square incident was a consequence of a bombardment that took place at a labor protest on 4th May 1886, in Chicago, at Haymarket Square. This incident started as a nonviolent demonstration in support of labors quitting for an eight-hour workday, the day after policemen shot one and harmed some labors. An unfamiliar individual threw an explosive bomb at the police as they began to disband the assemblage, and the bomb blast and following explosion occurred in the mortality of seven policemen and four noncombatants.