Arrange the bonds between h, o, and f from most polar to least polar based on electronegativity.
bonds to order:
o-f
h-f
h-o
h-h

The polarity order increase from left to right in the order on the basis of electron negativity difference b/w two elements in the periodic table

Explanation:

H-F is the most polar bond  so you can calculate the polarity  difference  

H-O is second in the list as  

O-F is third in the list as the electron negativity difference is less b/w these two .

H-H has zero polarity because they will cancel out the values .

the answer is d.) potassium

c. electrical charges of ionic bonds.