Ans is (b)..
But according to me (a) should also be possible..can someone pls tell where I am going wrong?
If it would be simply molar conductivity then your answer wild be right as shown in graph 1 in picture, but they have asked limiting molar conductivity or the conductivity at infinite dilution which will have a plot as in graph 2.
Since it tends to infinity, it cannot be calculated precisely.
So you have to solve it using Kohlrausch law, which corresponds to option B.
@Samarth_2020 try this too (Q111)