Answer:
1. “Biofeedback treatment has been considered as a suitable therapeutic approach for fecal incontinence, functional constipation, functional anorectal pain, IBS, functional dyspepsia, and aerophagia.”
I was only able to answer one but you can just search up your answer for the second.
Link for the first answer: https://www.nature.com/articles/ncpgasthep1150
Use the link if needed and mark me the brainiest if I helped!!
I'd have to say d. the hand, because every human (for the most part, no offence intended to anyone) has a hand and is able to make good (or bad, rather) use of it. It's what a person always has access to at any given time or place, even if they don't have access to one of the other options.