Is the provision (mutʿah) mentioned in this āyah obligatory or recommended?

Imām Ibn al-Jawzī (d. 597/1201) summarized the scholars' opinions in his book "Zād al-Masīr" as follows:

1. It is obligatory. Those who hold this opinion differ regarding which types of divorced women it is obligatory for, with three specific views: (a) It is obligatory for every divorced woman. [Reported from ʿAlī, al-Ḥasan, Abū al-ʿĀliyah, al-Zuhrī] (b) It is obligatory for every divorced woman except the one for whom a dowry was specified but the marriage was not consummated; in this case, she is entitled to half of the specified dowry. [Ibn ʿUmar, al-Qāsim ibn Muḥammad, Shurayḥ, Ibrāhīm] (c) It is obligatory for the woman divorced before consummation if no dowry was specified; if the marriage was consummated, there is no provision (mutʿah), but she is entitled to a dowry in accordance with her social status. [al-Awzāʿī, al-Thawrī, Abū Ḥanīfah, Aḥmad ibn Ḥanbal]

1. The provision is recommended, not obligatory, regardless of whether a dowry was specified, or whether consummation occurred. [Mālik, al-Layth ibn Saʿd, al-Ḥakam, Ibn Abī Laylā]