Question

1. My grandparent's / grandparents' house is on Lumley Road.​

Answer 1

My grandparents' house..................

Answer 2

Both "grandparent's" and "grandparents'" can be correct, depending on the context:

1. "My grandparent's house is on Lumley Road."

   • This means that one of your grandparents (either your maternal or paternal grandparent) owns a house on Lumley Road.

2. "My grandparents' house is on Lumley Road."

   • This means that both of your grandparents (either your maternal and paternal grandparents or two grandparents on one side of your family) jointly own a house on Lumley Road.

The choice between the singular possessive "grandparent's" and the plural possessive "grandparents'" depends on whether you are referring to one grandparent or multiple grandparents in the possession of the house.