Which statement correctly explains the aspect “Grammatical form of layta” in the example “لَيْتَ الشَّبَابَ يَعُودُ”?

Inshāʾ and Tamannī: Requests, Wishing, Exhortation, and Reproach

• Defining taḥḍīḍ — Why do you not strive? Do strive!
• Grammatical form of layta — Would that youth returned.
• Wishing versus exhortation — Would that / Why not (do it)?
• Requesting and non-requesting inshāʾ — Requesting and non-requesting inshāʾ.