Element 'B' forms ccp structure and 'A' occupies half of the octahedral voids, while oxygen atoms occupy all the tetrahedral voids. The structure of bimetallic oxide is :

Correct option is D. AB2O4
We know,
No. of tetrahedral voids = 2 × no. of octahedral voids (or no. of atoms in CCP unit cell)
Number of atoms of B in the unit cell, ZB = 4; Note: Since, B forms ccp structure.
Number of atoms of A in the unit cell, ZA = 4 × 1/2 = 2; Note: Since occupies half of the octahedral voids.
Number of atoms of o in the unit cell, ZO = 8; Note: Since O occupies all the tetrahedral voids.
The formula of bimetallic oxide is AZABZBOZO = A2B4O8 = AB2O4
Option D is correct.