Final Answer:
Battle of Actium b) The Battle of Actium occurred in 31 BC, and it was a battle between Octavian and Cleopatra.
Step-by-step explanation:
The Battle of Actium took place in 31 BC, making option (b) the correct choice. The primary contenders in this naval engagement were Octavian (later known as Emperor Augustus) and Cleopatra, the Queen of Egypt. The battle was a pivotal moment in the final war of the Roman Republic, and its outcome led to the establishment of the Roman Empire under Octavian's rule.
Mark Antony, who had been allied with Cleopatra, also played a significant role in the events leading up to the Battle of Actium. However, the primary forces involved in the battle were Octavian's fleet against the combined forces of Cleopatra and Mark Antony.