So he is given in this verse an option...

So he is given in this verse an option: if he chooses to fast, he should fast for three days. And the fast of one who cannot offer a sacrifice at the pilgrimage is also obligatory; Allah Almighty says, ‘Whoever benefits by combining the visit with the pilgrimage (should take) what offering is easy (for him) to obtain; but he who cannot find (any offering) should fast for three days during the pilgrimage and for seen days when you return; these (make) ten (days) complete’ (Holy Qur’an, 2:196).