Information:  - Augustus (23 September 63 BC  19 August 14 AD) was the founder of the Roman Principate and considered the first Emperor, controlling the Roman Empire from 27 BC until his death in AD 14.  - Publius Ventidius Bassus, or in full, "Publius Ventidius Publii filius Bassus", "Publius Ventidius, Publius's son, Bassus" was a Roman general and one of Julius Caesar's protégés. He won impressive victories against the Parthians which resulted in the deaths of key leaders - victories which redeemed the losses of Crassus and paved the way for Antony's incursions. According to Plutarch in his "Life of Antony", the three military victories of Ventidius over the Parthians singularly resulted in the only award (up to the time of Plutarch's writing) to a Roman general of the triumphal ceremony for victory over Parthians.  - Gaius Julius Caesar (13 July 100 BC  15 March 44 BC), known as Julius Caesar, was a Roman politician, general, and notable author of Latin prose. He played a critical role in the events that led to the demise of the Roman Republic and the rise of the Roman Empire.  - Marcus Antonius (Latin: ; January 14, August 1, 30 BC), commonly known in English as Mark or Marc Antony, was a Roman politician and general who played a critical role in the transformation of the Roman Republic from an oligarchy into the autocratic Roman Empire.  - The Battle of Philippi was the final battle in the Wars of the Second Triumvirate between the forces of Mark Antony and Octavian (of the Second Triumvirate) and the forces of the tyrannicides Marcus Junius Brutus and Gaius Cassius Longinus in 42 BC, at Philippi in Macedonia. The Second Triumvirate declared this civil war ostensibly to avenge Julius Caesar's assassination in 44 BC, but the underlying cause was a long-brewing class conflict between the "ancien regime" represented in the Senate (Optimates), and the rising class (Populares).  - Titus Labienus (c. 100 BC  March 17, 45 BC) was a professional Roman soldier in the late Roman Republic. He served as Tribune of the Plebs in 63 BC, and is remembered as one of Julius Caesar's lieutenants, mentioned frequently in the accounts of his military campaigns. He was the father of Quintus Labienus.  - The Battle of the Cilician Gates in 39 BC was a decisive victory for the Roman general Publius Ventidius Bassus over the Parthian army and its Roman allies who served under Quintus Labienus in Asia Minor .  - Parthia (Parava, , Paraw, , Pahlaw) is a historical region located in north-eastern Iran. It was the political and cultural base of the Arsacid dynasty, rulers of the Parthian Empire (247 BC  224 AD).  - The Second Triumvirate is the name historians have given to the official political alliance of "Gaius Octavius" (Octavian, Caesar Augustus), "Marcus Antonius" (Mark Antony), and "Marcus Aemilius Lepidus", formed on 27 November 43 BC with the enactment of the "Lex Titia", the adoption of which is viewed as marking the end of the Roman Republic. The Triumvirate existed for two five-year terms, covering the period 43 BC to 33 BC. Unlike the earlier First Triumvirate, the Second Triumvirate was an official, legally established institution, whose overwhelming power in the Roman state was given full legal sanction and whose "imperium maius" outranked that of all other magistrates, including the consuls.  - Quintus Labienus Parthicus (died 39 BC), the son of Titus Labienus, was a Roman republican general, later in the service of Parthia. After the then main political power in Rome, Julius Caesar, was murdered by a conspiracy in 44 BC, Labienus took the side of the pro-republic conspirators, led by Brutus and Cassius, the latter of whom he served in the capacity of an ambassador to the Parthians. After Brutus and Cassius fled east to Macedonia and were defeated there in the Battle of Philippi by Caesar's imperialist successors (the Second Triumvirate, particularly Mark Antony and Caesar's heir Octavian, the future emperor Augustus), Labienus joined the Parthians.     After reading the paragraphs above, we are interested in knowing the entity with which 'battle of the cilician gates' exhibits the relationship of 'instance of'. Find the answer from the choices below.  Choices: - 1  - august  - award  - base  - battle  - cause  - ceremony  - conflict  - death  - dynasty  - emperor  - empire  - final  - iran  - january  - july  - key  - march  - military  - name  - official  - oligarchy  - period  - politician  - professional  - region  - republic  - september  - service  - side  - three  - time  - year
A:
conflict