Which one of the following is paramagnetic?

The formation of molecular orbitals can be described by the linear combination of atomic orbitals. Which one of the following correctly represents the formation of bonding molecular orbital from the atomic orbitals having wave functions $\psi_A$ and $\psi_B$?

$A$ homonuclear diatomic gas molecule shows $2$-electron magnetic moment. The one-electron and two-electron reduced species obtained from the above gas molecule can act as both oxidizing and reducing agents. When the gas molecule is one-electron oxidized, the bond length decreases compared to the neutral molecule. The gas molecule is

The molecule having one unpaired electron is

The molecular orbital theory supports paramagnetic behaviour of:

Which one of the following does not exhibit paramagnetism?