Answer is A. There is no error
The comma is necessary since there is a pause in the sentence. When naturally speaking, it makes the most sense. Also, “before they went to town” is a prepositional phrase and deserves a comma right after it.
Hi !!
whose introduces a relative clause indicating a posession by people, animals, things....
the owner is before whose and the people, animal, thing just behind.
An example =
My friend, whose sweater was lost, had to go back to the restaurant to try to find it.
We met our friend whose sweater was lost.
Kate whose sweater was lost was very cold.
Tom whose sweater was lost came with us to warm up in a coffe shop.
Here are some examples. Sorry if my english isn't that good (I'm French) but I'm sure about whose
hope I helped :)
1 girl
2boy
3boy
4girl
5both
6both
7boy
8both
9girl
10boy
If you type this question in the white search bar on the main page. someone else asked this. It's a good answer