By "a system of built-in obsolescence" the author means ______.

A．no formal systems exist in modern industrial society

B．old people have no status in modern industrial society

C．young people have chances in modern industrial society

D．knowledge changes rapidly in modern industrial society

(1—2题共用题干)男性，53岁，突感胸背部剧烈疼痛，呈撕裂样痛，持续性难以忍受，右上肢血压165／60mmHg，左上肢130／70mmHg。

最有可能是什么疾病

A．多发性大动脉炎

B．肾动脉狭窄

C．马方综合征

D．动脉粥样硬化

E．主动脉夹层