Answer:
The correct answer is A. God.
Step-by-step explanation:
While the poem deals with the global turmoil after WWI,
Although Yeats was obscure about this, the reference to a "blood-dimmed tide", the fact that the ceremony of innocene is "drowned" transmits the reader an image of water rushing around him or her, pretty much like Noah's flood. Thus, the blood-dimmed tide can be a second flood punish humanity after the horrors of war.