My youngest had a difficult birth (twin B with hypoxic issues) and was not clear she would make it through her first night. She did.
She had special needs but was always a joy, and always made progress. That said, at 18 she was probably a 3rd grade level in most things, and would probably have never been able to live independently.
She tragically passed away at age 18 almost a year ago today. Just 5 months shy of her most treasured goal of graduating high school. Serena was a real person. A happy bunny that brought joy to those around her. Including complete strangers. One of her favorite lines was to say to anyone wearing a dress, classmate, teacher, stranger in the supermarket, “you look like a princess.” Strangers would take a second or three to process the young lady; diction, pronunciation, posture, etc just a little off, and 99 times out of 100 would beam and say “thank you!”
What the OP asks is an impossible scenario. That said, based on my experience, I would go with option one and aborted when profound conditions were recognized.
For Serena, this was not the scenario. It was a twin birth with a late 30’s mother, so considered high risk but otherwise no abnormalities.
I would not vote for option B, as then it would be the joy of birth and breath of life combined with knowing it would be for just a short while. Far short of when the baby would become a little person, with an obvious personality, starting to walk and talk back, etc.
IMHO, option C would be the most selfish. Does not consider the quality of life for the child during those few years. Does not consider the horrific emotional toll on the parents and caregivers. As a father, that would be an unthinkable existence hoping against all hope that things would be “normal” yet knowing that miracles like that happen only in Hallmark Christmas movies. For no rational hope that your child could thrive for a happy extended life would be torture.
YMMV, and I really wish I was not able to comment based on experience.