The conference the three men held at Luca in 56 BCE mainly served to
declare joint war on the Parthian Empire
formally dissolve the alliance among the three men
elect Caesar as sole consul for the following year
renew and extend the political cooperation among Caesar, Pompey, and Crassus✓Correct answer
Explanation
At Luca the three allies reaffirmed their cooperation after signs of strain and arranged future provincial commands and senior magistracies for two members. The conference renewed the partnership rather than dissolving it; it neither declared a joint Parthian war nor made Caesar sole chief magistrate.