Answer
Oxygen.
Step-by-step explanation
The trend of electronegativity in the periodic table is: electronegativity generally increases as you move from left to right across a period and decreases as you move down a group.
As a result, the most electronegative elements are found on the top right of the periodic table, while the least electronegative elements are found on the bottom left.
That is alkali metals have the lowest electronegativities, while halogens have the highest. Because most noble gases do not form compounds, they do not have electronegativities.
Therefore, from the given set of atoms, the atom that has the highest electronegativity is oxygen.