Which number can come in place of question mark (?) ?

Answer & explanation
Correct answer: option 2
From option (I) & (II)
1 –– 2 –– 3
1 –– 4 –– 6
Thus, we get that,
‘2’ is opposite to ‘4’
‘3’ is opposite of ‘6’
‘1’ is opposite of ‘5’
Look at the position I and IV carefully, two surfaces are common.
Therefore, the question mark in the position IV will be replaced by ‘6’