(A) is incorrect because it doesn't strengthen the stimulus. If most of the dwellings were made, in part, with limestone, then the building they are studying, which is also made, in part, with limestone, could, therefore, be a dwelling. Therefore, if anything, it slightly weakens the argument.
(B) is CORRECT because it helps strengthen the archaeologist's reasoning that the building the archaeologist is studying, which is made of quarts, granite and limestone (two of which do not occur naturally), is not a dwelling. If most of the buildings at the site that were not dwellings had a similar make up as the building they are studying, then that strengthens the conclusion.
(C) is incorrect because it doesn't matter. Who cares if most the buildings that were built from stones not naturally occurring in the area were not built with both quartz and granite? No one.
(D) is incorrect because even if most of them were used as dwellings, it doesn't strengthen the stimulus. If anything it slightly weakens the stimulus because it makes it more likely that the building being studied is also a dwelling.
(E) is incorrect because, just like (C), it doesn't matter. It does not strengthen the stimulus.
Hope that helps! Let me know if you have any other questions.
