Which of the following overlaps gives a `sigma` bond with `x` as internuclear axis?

Which of the following combinations is not allowed (assume z - axis as internuclear axis) ?

Which of the following orbitals will not form sigma bond after overlapping ?

Which of the following overlaps of atomic orbitals does not form pi -bond if z-axis is the internuclear axis?

Which of the following overlaps of atomic orbitals does not form pi -bond if z-axis is the internuclear axis?

Molecular orbital theory as developed by Hund and Mulliken concerns with the formation of molecular orbitals formed by linear combination of atomic orbitals. The electrons are present in these molecular orbitals. The molecular orbitals are filled. The molecular orbital configuration helps us to calculate bond order which gives information about the number of bonds present between atoms. The bond order is related to bond length and bond strength. Which of the following combination does ot give sigma MO (assume Z - axis as internuclear axis)

Which of the following combinations of atomic orbitals gives antibonding pi MO (assume z - axis as internuclear axis) ?