A little different one. Let's see each option. (d) Six needs one opposite to itself to fulfill the condition in the question but as is obvious from the figure this is not the case. Six and one are beside one another. So this die cannot fulfil the given condition.
(c) Here 3 and 4 are side by side which will again not allow the given condition to be fulfilled.
(b) Same here with 5 and 2.
(a) This is the only dice where the condition may fulfilled if the face opposite 5 and 2, face opposite 1 is 6 and face opposite 3 is 4, hence this dice can fulfil the required conditions.