Don't get hung up on selecting the absolutely correct answer for every multiple choice question. The fact is that absolutely correct is tough to achieve. Let's face it, life is full of what if's, subject to's and maybe but's and so is real estate. Also, problems faced in life are not conveniently arranged in four descending options, one of which is correct. However, MCQs have proven to be a very effective way to test knowledge. When writing an MCQ exam, look for the best answer of the four, not always the exact, perfect one. For example, four answer options in a math question are 11.3%, 22.6%, 18.7% and 16.7%, but your calculator produces 18.64%. The correct answer is obvious. The minor difference is probably due to rounding.