Is the Sunnah before the Dhuhr prayer two rak'ahs or one rak'ah, and is there a scholarly disagreement about that?

The Sunnah (supererogatory prayer) before Dhuhr (noon prayer) is not Witr (an odd-numbered prayer). It is either two rak'ahs with one Tasleem (salutation of peace), or four rak'ahs with two Tasleems, and the Muslim has the choice between them. Some scholars prefer performing it as four rak'ahs with two Tasleems at home, and two rak'ahs with one Tasleem in the mosque.