IMO D.

in A,B "it" doesnt have an antecedent.

E unnecessarily uses passive construction. Also, I think subject should be Settlers, but not settlers' homes.

Now, comes the tough part.

I am not quite sure how to eliminate now. But, I can list 2 ways how i came down to D.
1) "them" in C can refer to homes or settlers. So ambiguty.
2) E uses the "making do without" construction and uses an incorrect part before it. So probably the part after comma must be right. So chose D.
(This is by no means a way to solve it. But I would have chosen D based on this approach. an Educated Guess I would say.)

I do not know what "making do without" means. Need some experts to advice.

HI,
"MAKE DO" means "manage" , here "making do" is a modifier modifying the action of previous clause.
thanks.
hence :d:

MAKE DO= To use a poor substitute when one does not have the right thing

Nice question
OA pls