A compound is formed by two elements X and Y. Atoms of the element Y (as anions) make ccp and those of the element X (as cations) occupy all the octahedral voids. The formula of the compound is-

1. X₂Y₃
2. XY₃
3. XY
4. X₂Y

Atoms of element B form hcp lattice and those of the element A occupy 2/3rd of tetrahedral voids. The formula of the compound formed by the elements A and B is :
1. A₂B₃
2. A₄B₃
3. A₄B
4. AB₃