Remember, these guys are SP two hybridized. And this carbon also donates an SP two hybridized orbital. So when we combine two atomic orbitals, we must form two molecular orbitals according to quantum mechanics. And so our lower end energy more stable molecular orbital will be due to the overlap of these green regions. And we will get the following SP two, SP two sigma bonding molecular orbital, or simply mo. So the two electrons, one electron in each of this carbon in each of these SP two hybridized orbitals will go into this lower in energy bonding molecular orbital.