求问一道DS

nanlisusan

[y] denotes the greatest integer less than or equal to y. Is d < 1?

(1) d = y - [y]

(2) [d] = 0

• AStatement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
• BStatement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
• CBOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
• DEACH statement ALONE is sufficient.
• EStatements (1) and (2) TOGETHER are NOT sufficient
• 想问一下各位大神，这道题为什么选D;
• 第一个条件里如果y＝[y]，那他们相减就是0，那么d<1; 但是y如果不是整数，y可以是2.3， 3.5， 4.5啊，那y－[y]不就大于0了嘛？
• 还有第二个条件，为什么就能把d的取值范围固定在 [d] <=d<1啊？