the degree of polarity of a covalent bond between two atoms is determined by calculating the difference in their

a)
atomic radii

b)
melting points

c)
electronegativities

d)
ionization energies

C) electronegativities

Explanation:

there is an electronegativity chart that will tell you the charge, then you can subtract between the two and use cut offs for the values to see if you have an ionic, polar covalent, or non polar covalent bond

it's all four options.