Select the opinion that will improve the underline part of the sentence. In case no improvement is needed, select ‘No improvement’. Keep him at arm’s length lest you may not repent in the long run.

Correct answer: lest you should

Explanation: The correct answer is D.✅ The word "lest" means for fear that or to avoid the risk of something happening, and it is always followed by a subjunctive verb form-commonly "should + base verb" or simply the bare infinitive. "Lest you may not" is grammatically incorrect and a double negative. Correct sentence: Keep him at arm’s length lest you should repent in the long run. ❌"Or you may not" changes the meaning entirely. ❌"Unless you may" is ungrammatical in this context. ❌"Lest you should" is the correct formal usage after "lest".