The verification tool used to confirm Required Assumption answers: negate the answer choice and check whether the negation destroys the argument. If the negated version makes the conclusion unsupportable, the original choice is a required assumption. If the argument still survives when the choice is negated, the choice is not required and is wrong. The Negation Test exploits the definition of a required assumption — something the argument depends on must, when denied, cause the reasoning to collapse.