Respuesta :

My Mother's old housethe one that was owned by her family for generations, i s deteriorating.               ^^                                                                                           ^^

D is the best answer choice because it is using an Interrupter meaning that the phrase inside the commas can be taken out and the sentence still makes sense. 
My best guess would be D. My mother's old house, the one that was owned by her family for generations, is deteriorating.

Hope this helps.