下图是电视剧《闯关东》朱开山(义和团失败，朱开山走上闯关东之路，在广袤荒凉的土地上和妻子儿女们白手起家，一路拼搏，最后一举成为哈尔滨重工业富商)一家从山东辗转逃亡到东北途中用到的四种交通工具。据此，对晚清的经济现象分析不正确的是（   ）

A．新旧交通工具并存，体现了晚清社会受工业文明的冲击

B．中国民族工业一定程度推动近代人民的出行生活新变化

C．近代列强的侵略加剧中国社会的贫穷落后

D．在近代社会转型中，中国社会经济以民族工业为主导

In a public-key cryptosystem, (71) encrypted with the public key can only be deciphered with the private key from the same (72) . Conversely, (71) encrypted with the private key can be decrypted only with the public key. Users can make their public keys (73) available or place them at a key distribution center or others to access. However, the private key must be (74) safe. In public-key systems there’s no (75) to find a safe channel for communicating a shared secret key.

A. binarytext B. hypertext C. plaintext D. supertext