It would be past tense because when you say something occurred you are saying that it has already happened
The second choice would be the answer
The claim in the passage, "Beyond Thirst: The Global Water Crisis" is this: "Left unchecked, the crisis will only worsen."
<h3>What is a Claim?</h3>
A claim is an opinion that is usually made at the introductory part of a text. In the second paragraph of the cited passage, the author claimed that there is an existing challenge with water, which left unchecked, will only worsen.
In the body of the passage, he supported this claim with proof.
Learn more about claims here:
brainly.com/question/2748145