Final answer:
The C-C bond is the least polar among the options given because carbon atoms have the same electronegativity, making it a nonpolar covalent bond.
Step-by-step explanation:
The bond that is least polar among C-C, C-N, C-O, and C-H is the C-C bond. Polarity in bonds is determined by the difference in electronegativity between the two atoms involved. Since carbon atoms have the same electronegativity, the C-C bond is a nonpolar covalent bond. On the other hand, bonds between carbon and other atoms such as nitrogen, oxygen, and hydrogen display varying levels of polarity due to differences in electronegativity. The C-H bond is only minimally polar and its most significant intermolecular force would be dispersion forces.
The C-N bond is less polar than the C-O bond since nitrogen is less electronegative than oxygen. However, it is more polar than a C-C or C-H bond. The C-O bond is considerably polar due to the high difference in electronegativity between carbon and oxygen.