Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? correct choices change the meaning in important ways or leave out essential information. A. The structural role of steel beams made it possible to hang stone or brick walls instead of using them for support as traditional architecture had. B. Opening up walls and corners was unimportant in traditional architecture so walls and corners were solid until steel-beam buildings were designed. C. In steel-beam buildings, the beams provide the structural support, so walls and corners can be opened up in ways not possible in traditional architecture. D. In a steel-beam buildings the walls are essentially hung from the internal skeleton of steel beams, which means that stone and brick masonry are not needed.