Carbon Has a Valency of Four

Carbon has a valency of four. Which of the following are correct deductions based on this information? Select all that apply.

A) Carbon needs to share two pairs of valence electrons to achieve a full valence shell.
B) Carbon needs to share four pairs of valence electrons to achieve a full valence shell.
C) One atom of carbon can form four single covalent bonds.
D) One atom of carbon can form one double bond and two single bonds.
E) One atom of carbon can form two single bonds and two double bonds.