21. It can most reasonably be inferred from the passage that the author views the statement by Frampton in the highlighted portion as:
Your Answer is
Correct Answer is D
Explanation
According to the title, Frampton believes that glass building is becoming popular again. The whole article mainly describes the characteristics and advantages of glass building. So the author also supports glass building. Item D fits the question.
Item AB: This statement is not exaggerated or simplified.
Item C: Glass architecture has become a reality.