Which from following is an example of two dimensional nanostructures?

A conductivity cell containing $$0.001 \mathrm{~M} \mathrm{~AgNO}_3$$ solution develops resistance $$6530 \mathrm{ohm}$$ at $$25^{\circ} \mathrm{C}$$. Calculate the electrical conductivity of solution at same temperature if the cell constant is $$0.653 \mathrm{~cm}^{-1}$$.

What is the number of $$\mathrm{sp}^3$$ hybrid carbon atoms in $$\mathrm{HO}\left(\mathrm{CH}_2\right)_3 \mathrm{CH}\left(\mathrm{CH}_3\right) \mathrm{CH}\left(\mathrm{CH}_3\right)_2$$ ?

Which from following thermodynamic properties is a path function?