Sentence Correction

A 2009 study from the California State Housing Authority concluded that conversion from ownership to rental properties has often been difficult; it has been more common for some townhouses and other "attached" homes that are relatively small and old, located in central cities.

A) difficult; it has been more common for some townhouses and other "attached" homes that are relatively small and old, located in central cities.
B) difficult; it has been more common for some townhouses and other "attached" homes that are relatively small, old, and that are located in central cities.
C) difficult; it has been more common for some townhouses and other "attached" homes, which are relatively small and old, and located in central cities.
D) difficult: It has been more common for some townhouses and other "attached" homes that are relatively small and old and located in central cities.
e) difficult: It has been more common for some townhouses and other "attached" homes that are relatively small and old, and located in central cities.

Please explain.

A) difficult; it has been more common for some townhouses and other "attached" homes that are relatively small and old, located in central cities.
"small and old" and "located in central cities" are a part of a list with two items, hence they should be connected with "and"
B) difficult; it has been more common for some townhouses and other "attached" homes that are relatively small, old, and that are located in central cities.
home that and relatively small ... and that are ...
This signifies two types of homes as
Which - is used to describe something that you've already defined.
That - is used to narrow down a list of things that is undefined.
C) difficult; it has been more common for some townhouses and other "attached" homes, which are relatively small and old, and located in central cities.
Which - is used to describe something that you've already defined. So, here we have to use that.
D) difficult: It has been more common for some townhouses and other "attached" homes that are relatively small and old and located in central cities.
Correct
E) difficult: It has been more common for some townhouses and other "attached" homes that are relatively small and old, and located in central cities.
Here we have a list which has two entities only: "small and old" and "located in central cities"
And for a list with two entries, we do not need to put a comma before "and"

prachi18oct wrote:A 2009 study from the California State Housing Authority concluded that conversion from ownership to rental properties has often been difficult; it has been more common for some townhouses and other "attached" homes that are relatively small and old, located in central cities.

A) difficult; it has been more common for some townhouses and other "attached" homes that are relatively small and old, located in central cities.
B) difficult; it has been more common for some townhouses and other "attached" homes that are relatively small, old, and that are located in central cities.
C) difficult; it has been more common for some townhouses and other "attached" homes, which are relatively small and old, and located in central cities.
D) difficult: It has been more common for some townhouses and other "attached" homes that are relatively small and old and located in central cities.
e) difficult: It has been more common for some townhouses and other "attached" homes that are relatively small and old, and located in central cities.

Please explain.

Hi- do you mind sharing the source of the question...

I jennifer please explain why B is incorrect. I was looking for X ,Y and Z type answer. What is wrong in B?