I think it would go after
Noun1.the subject of a talk, a piece of writing, a person's thoughts, or an exhibition; a topic."the theme of the sermon was reverence"
Answer:
Physical water scarcity occurs when there is not enough water to meet all demands. ... Economic water scarcity is caused by a lack of investment in water or a lack of human capacity to satisfy the demand for water, even in places where water is abundan
Explanation:
The answer is B. object because the world is an objest