Final answer:
Alexander the Great expanded his conquests and empire following his father Philip II's death, pushing into the Persian Empire and beyond.
Step-by-step explanation:
The death of Philip II had a profound effect on Alexander the Great, leading to the expansion of his conquests and empire. Following his father's assassination, Alexander swiftly dealt with the immediate threats such as invasions and rebellions.
He then pursued his father's goal of avenging the prior Persian invasions against Greece by leading a campaign against the Persian Empire. After the decisive victories at the battles of Issus and Gaugamela, Alexander claimed the Persian throne and continued his conquests into central Asia and India, greatly enlarging the Macedonian Empire.
The correct answer, based on the impact of Philip's death on Alexander's following actions, is: c) Alexander expanded his conquests and empire.