Three different positions of the same dice are shown, the faces of which are marked with the letters A, B, C, D . E and F. Select the letter that will be on the face opposite to the face having the letter “D’.

B

Step 1)  This dice marked by alphabets A , B , C ,D , E , F

Step 2)  According to question  B  is common in all the dices and it shares it's boundary with all A, C, E ,F except D.

Step 3)  So, the number D is on the face opposite the face showing 'B'.