I think this is the correct answer because it specifically adresses one architectural construction. Remember that in all disciplines the accumulated knowledge developed over the years is too extensive to embrace. This is the reason disciplines are divided in subjects. In this case if you want to do a research you need to be able to delimit the subject, otherwise you would have so much information abailable your objectives and results would turn vague. Options A, B and C, are too broad, the information required is huge, it covers too many years of history (A and B), or too many elements to take into consideration (C). Option D, limits the information to one specific element that can be easily traced in time and space.
Serial arguing is when multiple arguments erupt over a period of time about the same issue. Here, Matt and Kim have multiple conflicts (several times) over a period of time (a week) about the same issue (dirty dishes being left in the sink).
