Silicon's Atomic Number Is 14;in the Periodic Table It Is

Silicon's atomic number is 14;in the periodic table it is directly beneath carbon.Silicon is abundant in the Earth's crust,yet,unlike C,N,O,and H,silicon is not a common element in organisms.What about the atomic structure of silicon probably accounts for this?

A) The nucleus of silicon is probably too small to form long chains of Si-Si molecules (analogous to long chains of carbon molecules) .
B) The nucleus of silicon is probably too big to form long chains of Si-Si molecules (analogous to long chains of carbon molecules) .
C) Silicon only has three valence electrons,so it can make fewer covalent bonds than carbon.
D) Silicon is too electronegative to be an element common in living organisms.