Sunnah before the Salah of Zohr

Is there 2 or 4 Rak’at Sunnah before the Farz of the Salah of Zuhr? Some Hadith say that Rasulullah (Sallallaahu Alaihi Wasallam) was performing 2 Rak’at just as some Hadith say that Rasulullah (Sallallaahu Alaihi Wasallam) was performing 4 Rak’at. However the mention of 4 Rak’at is made in most Hadith. And most of the time, Rasulullah (Sallallaahu Alaihi Wasallam) was performing 4 Rak’at. That is why, according to Imam Tirmizi, the majority of the Sahaabah-e-Kiraam (Radiyallahu Anhum) and the Taabi'in had preferred to perform 4 Rak’at before the Farz of the Salah of Zohr.

[English version of "Sounnat avant namaz Zohar" – Al Jamiat – Vol.2 No.15]