Statement (A): Electro negativity is the property of isolated atom.                  

Statement (B): Noble gases have highest electronegative value i.e.,4.0                         

Statement (C): EN has no units

Is incorrect, the correct statement is because Electro negativity is the property of bonded and it has no units.

The correct statement is the electro negativity values of elements in Milliken scale will be 2.8 times more than Pauling scale value,  ${\left(\mathrm{EN}\right)}_M=(2.8){\left(EN\right)}_p$

E.N is applicable to covalent bonded molecules it has no units.

 E.N have units according to Mulliken scale.