Answer:
Correct answer is C. He divided the Roman Empire into a Western and Eastern Empire.
Explanation:
A is not correct as Republic collapsed in 1st Century BC and Diocletian ruled in 3rd and 4th Century AD.
B is not correct as this is contributed to Octavian August.
C is correct as he divided empire, and even choose his co-ruler.
D is not correct as this was done by Constantine The Great.