Who wondered why her mom hated her?

Choices:
A. her half sister
B. The narrator
C. Her sister
D. not enough information
The narrator
Yes, after my mother died I found out from my supposed half-sister that my dad was not my birth father. She was 19 yrs older than me and had been living in Colorado since I was young. I was born and raised in N.J. I did not see her she did not come to see us. I was grown, married, had children and was living in FL. when she showed up at my door with her husband. I was shocked since we never heard from her and I did not know she even knew where I lived. She stayed all of about 20 minutes, just long enough to very unpleasantly state that “my father is NOT your father and I am NOT your sister!”
I always wondered why my mom hated me SO much, I found out that both my mom and “dad" were having affairs while married and both had children by someone else. I have never met my birth father (to my knowledge) only know his name, but understand that he was the father of my supposed half-brother (which would make him my only whole sibling out of seven siblings.)
Obviously my oldest “half-brother", who is 20 yrs older than me, is not actually related to me either.
I don't have for sure “proof" about my other siblings, but they all have strong resemblances to my “dad" and each other. Growing up people would comment about how much I looked like my mom but I also was told a lot that you would never know me and my other sisters were sisters, we used to laugh about it as kids because my sisters (all light haired/light skinned) and I (dark haired/deeper skin toned) were very different in appearance but we “knew" we were sisters.
I also found out that my apparently ONLY whole brother, approximately 9 yrs older than me, did not even know his real fathers name even though he knew our “dad“ was not his birth father.