In Some Vintage Science Fiction Movies,space Travelers Find Themselves on a Planet

In some vintage science fiction movies,space travelers find themselves on a planet orbiting a distant star in which there are curious forms of life based on silicon instead of carbon.Although the story clearly is sci-fi,there is an aura of plausibility in the choice of silicon,an atom with 14 protons,in place of carbon as this alien life-form's central atom.The reason is that silicon:

A) has four electrons in its outermost shell.
B) has one more proton than carbon, so is very similar to it.
C) is an isotope of carbon.
D) is lighter than carbon.
E) is heavier than carbon.