The correct option is A H2>B2>Li2
H2,Li2,B2 are not equal stable. Li atom is much larger in size than H−atom. The bond length in Li2 is much larger than bond length in H2. Moreover, Li2 molecule has two electrons in the antibonding molecular orbital while H2 has no electrons in the antibonding molecular orbital. Thus, Li2 is less stable than H2 (Bond energy of Li2=110 kJ mol−1+ Bond energy of H2=438 kJ mol−1). Boron atom is smaller than lithium atom but larger than hydrogen atom.The B2 is more stable than Li2 but less stable than H2 (Bond energy of B2=290 kJ mol−1).