Final answer:
In a modus tollens argument, the second premise denies the consequent of the first premise. This leads to the conclusion that the antecedent must also be false. The correct option is d.
Step-by-step explanation:
In modus tollens, the first premise typically takes the form of a conditional statement, 'If X, then Y'. The second premise of a modus tollens denies the consequent (the Y part) of the first premise, stating that Y is not true.
Given that the consequent represents a necessary condition within the conditional statement, we can infer that if the consequent is false, then the antecedent (the X part) must also be false. Therefore, the correct answer to the question 'In a modus tollens, the second premise:' is d. denies the consequent of the first premise.
This form of argument asserts that if the necessary condition is not met, then the sufficient condition cannot have occurred. The correct option is d.