How should one
    pray the four Sunnah rak’ahs of Zuhr?
Question

                When one prays the four Sunnah
      rak’ahs of Zuhr, before or after [the fard prayer], or the Sunnah of ‘Asr,
      should he say the Salaam once or twice? [i.e., should he put all four rak’ahs
      together, or pray them two by two?]
Praise be to Allah.It is permissible for him to pray them with one
    tashahhud or two [i.e., he may pray them all together or two by two], but it is preferable
    to say the salaam twice [to pray them two by two].