下列是关于名著的理解，正确的一项是（  ）

A．大观园中林黛玉的居所是怡红院 ，凤姐弄权是在水月庵。

B．堂吉诃德第一次出行，遇见一伙商人。他把他们当作一队兵马，挺枪跃马冲杀过去。结果，他把骡夫打下马来，骡夫躺在地上动弹不得。

C．朵拉既有外在的美貌，又有内心的美德，她最后与大卫的结合，这种完美的婚姻使小说的结尾洋溢一派幸福和希望的气氛。

D．伽西莫多是圣母院的敲钟人，外形奇丑，心地善良。他因副主教克洛德对他的养育之恩而极其感激。在受刑时对爱斯梅拉达的送水感动不已。他勇劫法场，把爱斯梅拉达救到圣母院悉心照顾，并深深爱上了她。最后他把邪恶的克洛德杀死，临死前抱着爱斯梅拉达的尸体逃入山洞。他是理想化的人物，作者在他身上倾注了人道主义精神。

Most computer systems are (16) to two different groups of attacks: Insider attacks and outsider attacks. A system that is known to be (17) to an outsider attack by preventing.
(18) from outside can still be vulnerable to the insider attacks accomplished by abusive usage of (19) users. Detecting such abusive usage as well as attacks by outsides not only provides information on damage assessment, but also helps to prevent future attacks. These attacks are usually (20) by tools referred to as Intrusion Detection Systems.

A．reliable

B．secure

C．indestructible

D．steady