Molecular orbitals formation involved in the combination of same type atomic orbitals which also have same symmetry for diatomic molecules.So the correct combinations to the formation of molecular orbitals are,

1s + 1s -----> Ï1s + Ï*1s

2s + 2s -----> Ï2s + Ï*2s

2pz + 2pz -----> Ï2pz + Ï*2pz

2py + 2py -----> Ï2py + Ï*2py

2px + 2px -----> Ï2px + Ï*2px