Explain why there is a phenomenal decrease in ionization enthalpy from carbon to silicon?

Options

1. AThe increase in electron shielding and atomic radius from carbon to silicon leads to a decrease in the effecti
2. BThe electron-electron repulsion in the outermost shell increases from carbon to silicon, reducing the ionizati
3. CSilicon has more unpaired electrons in its outer shell compared to carbon, making it easier to remove an elect
4. DThe presence of d-orbitals in silicon allows for greater electron delocalization, resulting in a lower ionizat