Carbon and Other Elements in Period 2 Are Relatively Small

Carbon and other elements in Period 2 are relatively small in size compared to other elements because

A) they have few electrons, and those electrons are held close to the nucleus.
B) the electrons in these elements take up less space than in other elements.
C) they are found mostly in biological systems.
D) they form both single, double, and triple bonds, and must be small in order to do this.
E) All of the above.