Choose the correct answer

Why does the ending of لَا يَفْعُلْنَ remain ـنَ (retains Noon) even though prohibitive لَا is a governing jazm-causing particle?

Conjugating the standard Prohibitive Verb (Active & Passive)

• Because it is a subject pronoun which is indeclinable (mabni)
• Due to a printing exception
• Because it is a passive verb
• It has dual letters