这个否定句是用something还是anything

这个否定句是用something还是anything
 
这个否定句是用something还是anything? 请看题：
“If you want a necklace, I’ll buy one for you at once.” “Oh, no. A necklace is not _____ that I need most.http://yingyu.chazidian.com
A. anything                        B. something
C. nothing                          D. everything
【陷阱】此题容易误选A，机械地套用以下规则：something 用于肯定句，anything 用于否定句或疑问句。
【分析】当然以上规则在通常情况下是有效的，但此句不属通常用法。此题的最佳答案应是B，something 在此的意思不是“某种东西”，而是指“那种东西”或“这种东西”，即心中最想要的那种东西(相当于 the thing)。同样地，下面几题的最佳答案也是 something，而不是 anything(from http://yingyu.chazidian.com)：
(1) It’s not _____ that we want to talk about; let’s change the subject.
A. anything                        B. something
C. nothing                          D. everything
(2) It’s not _____ I enjoy; I do it purely out of a sense of duty.
A. anything                        B. something
C. nothing                         D. everything
(3) Self-control is not _____ that comes with your birth.
A. anything                        B. something
C. nothing                         D. everything
(4) This is not _____ that would disturb me anyway.
A. anything                        B. something
C. nothing                         D. everything