The type of bond between atoms in a molecule of co2 (electronegativity difference = ~1)
a. hydrogen bond
b. ionic bond
c. polar covalent bond
d. pure covalent bond
e. metallic bond

Carbon dioxide, or , is a pure covalent bond. 

pure - it's non-polar, because it's a linear & symmetrical bond.

covalent - covalence is when 2 electrons are shared by a pair of atoms. in the case of carbon dioxide, it's three atoms with  an oxygen atom on the right, an oxygen atom on the left, and a carbon atom smack in the middle. 2 of carbon's extra electrons are shared with the right oxygen, and 2 other extra atoms are shared with with left oxygen.