Would you please choose one

Quick treatment of a snakebite can prevent serious or long-term medical problems. First, the victim should wrap a bandage tight two to four inches above the bite, applying pressure but not cutting off the blood flow to the area. Second, he or she should immobilize the bitten area to avoid increasing blood circulation, as it makes the venom spread through [the / his or her / their] body quicker.

Which is best in the brackets?Or what else better fits in them?