Choose the correct verb: “It ______ useless to persuade a stubborn man.”

Correct answer: Is. The sentence states a general truth, so the simple present “is” is correct.

• Were: “Were” does not agree with the singular subject “it” here.
• Was: “Was” is past tense, but a general truth takes the present tense.
• None of these: “None of these” is incorrect because “is” is correct.