Bulugh al-Maram
Book 7, Hadith 41
Arabic hadith text
وَلِمُسْلِمٍ: { فَهُوَ بِالْخِيَارِ ثَلَاثَةَ أَيَّامٍ } 1 .1 - مسلم ( 1524 ) ( 24 ).
Translation
Muslim has
"He has three days in which to decide to keep them or not."