King David's grandmother?

[DILCIA]

I have a question that was given to a friend of mine by a priest.
Who was David’s grandmother?
Now I assume he meant King David so it would be Jesse’s mother or his mother in law. So she could be Obed’s wife but whoever she is I can’t find any mention of her with or without a name.
I wonder if it is a kind of “trick” question and doesn’t mean his biological grandmother.
I don’t know when my friend will get the answer and I said I would keep trying to find out.
Might it be somewhere other than the Bible perhaps some historical writings?

 

[Joe_Kelley]

I wonder if he meant great-grandmother or great-great grandmother. **Matthew 1:5 **

Salmon the father of Boaz, whose mother was Rahab. Boaz became the father of Obed, whose mother was Ruth. Obed became the father of Jesse,

Both women were considered quite disreputable.  Rehab kept a saloon or worse, but even worse Ruth was a Moabite. **Deuteronomy 23:4**

No Ammonite or Moabite may ever be admitted into the community of the LORD, nor any descendants of theirs even to the tenth generation,

This would bar David from the Jewish congregation.