Polar Covalent.
This is because both Calcium (Ca) and Carbon (C) are non metals, thus eliminating the ionic option.
It is polar covalent rather than nonpolar covalent due to the fact that the electrons in a polar covalent bond are shared unequally while those in a nonpolar bond are shared equally.
This can be determined by looking at the amount of valence electrons; if the electrons cancel each other out, it is shared equally. If not, it is shared unequally.
Hope this helps!