How Were the Violent Deaths of Tiberius and Gaius Gracchus

How were the violent deaths of Tiberius and Gaius Gracchus a turning point in the history of the Roman republic?

A) Their deaths broke with the traditional taboo against political violence and introduced factions into Roman politics.
B) Their deaths saw the end of the democratic reforms enacted during the republic, which had given commoners the majority say in political life.
C) Their murder at the hands of senators convinced other senators that a strong, sole ruler was needed to prevent civil war.
D) Their murders made the landless commoners realize that they too could dictate policy through the threat of violence.