Class A: Be elected Consul
Class B: Be elected Proconsul
Class C: Be elected Praetor (optional)*
Bonus: Gain the rank of Ex-Consul, +1 to NPC Interactions (stacked with tier I), +2 if Class C completed)
*Although appearing last, the praetorship was a step in the cursus before Consul, so in this case Class C should be completed before any of the rest.
Tier III
Class A: Win a triumph
Class B: Annex lands for Rome OR defeat a tribe/enemy/people for Rome.
Class C: Become a patron of Rome OR be elected Censor (Build a tier IV building, OPTIONAL)
Bonus: become the first among equals. Be warned, this might not be popular. +3 to NPC Interactions, +4 if the Class C condition is met.