If teresa's daughter is my daughter's mother who am i to teresa

Teresa is your mother in law / you are Teresa's son/daughter in law

If you give everyone a name it's a lot easier. So we have Theresa. The person who is related to you somehow.
She has a daughter (let's call her Erica)
Erica is my daughter(Janet)'s mother.
Janet is my daughter. Erica is her mother.
Me and Erica are Janet's parents.
Theresa is Erica's mom. If me and Erica are married, she's my mother in law. If not we can give her the title of my daughter's grandmother.

SOO there you have it. She's my daughter's grandmother.

The answer would be analytical reasoning.

According to the “the stand” by stephen king, became the longest book published by king at 1152 pages