50 Which of the following best summarizes the main purpose of the passage?
(A)To emphasize the safety of underground structures like coal mines during natural disasters.
(B)To provide a detailed comparison between the seismic activity in Tangshan and Haicheng.
(C)To explain the causes and consequences of the Tangshan earthquake while highlighting its importance to modern safety.
(D)To argue that the official death toll reported by the Chinese government was intentionally inaccurate.