Explanation:
It is known that when we move down a group then there will be increase in size and decrease in electronegativity. Whereas when we move across a period then there is decrease in size and increase in electronegativity of an atom.
Therefore, out of the given options oxygen will be most electronegative in nature whereas potassium will be the least electronegative in nature.
Thus, we can conclude that electronegativity in increasing order will be as follows.
K < Mg < P < O
