The correct passive form of the given sentence is:

☀ Let him not be insulted.

Explanation:

The active sentence is "Do not insult him." To convert this into the passive voice using "let," we use the structure "Let + object + be + past participle." So, "him" is the object in the active sentence, and the passive form will be "Let him not be insulted."

Now, let's analyze the other options:

☀ Let he not be insulted. This option is incorrect because "he" should be replaced with "him" in the passive construction.

☀ Let not he be insulted. This option is also incorrect because the word order is incorrect. In the passive construction, "not" comes after "let" and before the verb "be."

☀ Let not him be insulted. This option is incorrect because "not" should come after "let" and before the verb "be." The correct form is "Let him not be insulted."