Which element has the highest electronegativity?

Which of these has no unit?

According to the Mulliken scale,which parameters are required to determine electronegativity?

Consider the following.
Statement-$I$ : The order of electronegativity of $B, Al, In, Tl$ is $B > Tl > Al > In$.
Statement-$II$ : Boric acid is a weak protonic acid.
The correct answer is

Given below are two statements :
Statement $I$ : The electronegativity of group $14$ elements from $Si$ to $Pb$ gradually decreases.
Statement $II$ : Group $14$ contains non-metallic,metallic,as well as metalloid elements.
In the light of the above statements,choose the most appropriate from the options given below :

The electronegativity of $C$,$H$,$O$,$N$ and $S$ are $2.5$,$2.1$,$3.5$,$3.0$ and $2.5$ respectively. Which of the following bonds is most polar?