Who was Serach's father?

שרח בת אשר     

Who was Serach's  father?

1.    אשר

2.    ישוי

3.      son of Yishvi ) בן של ישוי

4.    מלכיאל

The Ramban (26:46) says the Targum Unkeles translates ושם בת אשר שרח,- "ושום ברת אתת אשר סרח

 The name of the daughter of Osher’s wife was Serach. (She wasn’t Osher’s daughter but his wife’s daughter)

The Ramban explains, Serach’s mother was married and had only one child (Serach)  Osher married her after her husband died.*

The Techeilas Mordechai (Kur Zahav) says that she was the daughter of Yishvi the son of Osher. When Yishvi died, Osher married his 

daughter in law. (Issur D’Orysa)** A second possibility is that she was the granddaughter of Yishvi and Osher married his son 

Yishvi’s daughter in law(Issur D’rabanan)

The Sefer Hayoshor*** says she was the daughter of  Malchiel ‎ben Eilam, (Eilam son of Sheim)

              *  Shu"t Chasam Sofer E,H,76 proves from here

                          the Halacha in Rema Ch.M. 42:15 "adopted children

                         can be called children in documents etc."

**Kodem Matan  Torah

                  ***Thanks to R. M.Appel Shlita (for Mareh Makom)