If Teresa's daughter is my daughter's mother, what am I to Teresa?

a. Grandmother
b. Mother
c. Daughter
d. Granddaughter
e. I am Teresa

3 answers

b. Mother

If Teresa's daughter is your daughter's mother, that means that Teresa's daughter is you. Therefore, you are Teresa's daughter, making you her mother.
If you are Teresa's daughter, then, duh, you are her daughter. So, C
Apologies for the confusion. You are correct.

c. Daughter

If you are Teresa's daughter, you are her daughter.