<p>Why is the primary purpose of the passage to explain an approach? And not justify an expense?</p>
<p>Also, how would you explain that question 13 in page 402? Why is the answer C, displaying a work of art to its best advantage and not E, providing elegant surroundings for exceptional paintings?</p>
<p>In question 9, the author is explaining his approach to studying cities:</p>
<p>"The following study is concerned with..."
"It aims to..."
"I want to find out not just who designed the buildings and when they were built but why they were built."</p>
<p>The author is explaining and justifying his approach.</p>
<p>It has nothing to do with justifying an expense.</p>
<p>For question 13, the paragraph isn't concerned with the elegance of the surroundings, or even with how exceptional the painting is.</p>
<p>The painting is "large." The author had "no wall and no room to do it justice." The painting needs "a vast, empty room." The author sells the painting and buys a smaller one.</p>
<p>If only he had a large house with large walls and plenty of room to admire the large painting from a distance, then he would be "displaying a work of art to its best advantage." That's what he wants, but doesn't get.</p>