وَإِنْ تَطَيَّبَ أَوْ حَلَقَ أَوْ لَبِسَ مِنْ عُذْرٍ فَهُوَ مُخَيَّرٌ: إِنْ شَاءَ ذَبَحَ شَاةً، وَإِنْ شَاءَ تَصَدَّقَ عَلَى سِتَّةِ مَسَاكِينَ بِثَلَاثَةِ أَصْوُعٍ مِنْ طَعَامٍ، وَإِنْ شَاءَ صَامَ ثَلَاثَةَ أَيَّامٍ
Translation: If he uses perfume, shaves, or wears prohibited attire for a valid excuse, he may choose: slaughtering one sheep, distributing three saʿs of food among six poor persons, or fasting three days.
Min ʿudhr is the crucial condition: for example, a medically necessary act otherwise prohibited in ihram. MukhaYYar means there is a choice among the three remedies, not an obligation to perform all three.
The feeding route is 3 saʿs for 6 needy people, equal to one-half saʿ each if distributed equally. The third route is 3 fasting days. Determining a valid excuse and modern measure equivalents needs separate expert application.