fuhank

我猜C, 因為他看的到B的顏色, 所以跟B一樣的顏色為只有1/3.

D_katherine

thanks for sharing

ryanlee1001

i think  is d

小子比利

過了五分鐘也不知道，現在的小學生題見真難。

fyh5b21

thanks for sharing

flyeee

C, because D didn't say anything.

雪神

asdfadbaedvbqwbed

krimino

A... because he can see in the reflection from B's pupil of the colour of his hat.

sank.e

C 因為D不知道 表示前面是一黑一

sai21103135

猜不出來，
$ z- ^, C8 q( p. l  ~1 yTVBNOW 含有熱門話題，最新最快電視，軟體，遊戲，電影，動漫及日常生活及興趣交流等資訊。d可能知道。

tiramitsupupu

thx for sharing

Henry027

D吧 如果係跟次序的話

xzw1113

不知道

xzw1113

不知道

sc7086

It should be C.  If C's hat is white, then D should know D's is black.  However, D could not answer right away, then it mean D saw a white and a black in front of D.  C can conclude that his hat is black.