This is a hard decision and it's difficult to pick. Both have a very brutal disadvantages with it, but also with a few advantages. But I thinks the rich one sounds more logical to pick.
If I choice A, I would get my basic needs to survive covered like hunger, thirst, sleep etc. without problems and I would also get many opportunities which I wouldn't have as poor. I would have the opportunities to support charity organizations, traveling around the world and if I also were famous, I could change the world with speeches. If I have a lot of moneys, I can also afford things I needs in order to make arts. I can afford stuffs to draw, take photography etc. If I pick A, I can't medical or social transition, but the thread didn't say anything about clothes style. I could still wear masculine clothes and have a masculine hairstyle. Style can ease a bit at the dysphoria, but aren't so effective as medical transition. Many celebrities and rich people are known for undergoing cosmetic surgeries. If a celebrity can undergo a cosmetic surgery to get bigger boobs (breast implants), they can also get breast reduction surgery. It doesn't need to be counted as medical transition, because it exist cis people who underwent such thing either for cosmetic purposes or due back problems. A trans woman who picked A could also get FFS for cosmetic purposes, if she wanted to. It exist people from both genders who underwent a facial surgery to look like female celebrities like Kim K. My point is it doesn't have to be trans related. You can also live as yourself in secret at home. It's just you can't medical or social transition, and nor can you tell the world public about your true gender. What you do when you're home alone is not any body else's business. You can still chat with people at anonymous forums about trans stuffs.
If I picked B, I would struggle with daily things due poverty. Hunger, place to sleep etc. would be a problem. Living as a homeless person doesn't sound fun at all. If I was a cis person, I would probably not know anything about being trans. I thinks it would be hard to be grateful for being cisgender if you both doesn't know how being transgender is and you face problems which distract you to enjoy the cisgender thing. Covering the basic needs would be a daily struggle. So I thinks it wouldn't be a funny life.
So if I had to pick, I think it would be A.