Answer: Option (b) is the correct answer.
Explanation:
It is known that when we move down a group there there is decrease in electronegativity. Whereas when we move from left to right in a period of periodic table then there is increase in electronegativity of the elements.
For example, iodine, rubidium, yetterbium, and palladium are all period 5 elements.
In this period, out of the given options iodine is at the bottom right hand side whereas rubidium is at the bottom left hand side.
Therefore, we can conclude that rubidium is most likely to have the lowest electronegativity.
