Is it recommendable for the Mufrid and Qarin to offer a sacrifice if they wish to do so?

The sacrificial animal (hadi) is obligatory for one performing Hajj al-Qiran (combining Umrah and Hajj), while for one performing Hajj al-Ifrad (Hajj alone), it is only recommended and not obligatory. This is based on the Almighty's saying: "Then whoever takes advantage of Umrah to Hajj [shall give] what can be obtained with ease of sacrificial animals."