I have the same question on my history test.
if your options are:
A. He lowered taxes and gave land to the poor.
B. He allowed all religions to exist in Rome.C. He withdrew all Roman military units from areas north of the Alps.D. He divided the empire into two parts, each with its own emperor.Then the answer is D. "He divided the empire into two parts, each with its own emperor". This is because Diocletian realized that the Roman Empire was too large to rule on its own, so, in order to fix this and other problems he split the Roman Empire into two parts, the Western Empire (based in Rome) and the Eastern Empire (based in Byzantium). One empire would rule each area separately.