Electronegativity of aluminium is 1.5. Electronegativity of thallium is
Electronegativity order :B > Tl >In > Ga > Al
Tl Electronegativity is greater than that of Al,Given Al Electronegativity is 1.5,hence Tl Electronegativity should be greater than that of 1.5.
Greater than 1.5 two options are there ,those are second and fourth options .
On pauling scale highest Electronegativity element is F,its Electronegativity value is on Pauling scale is 4.0.Therefore fourth option is wrong.
Then option 2 is correct.