(A) :One molar aqueous solution (d=1gm/cc) has always higher concentration than one molal.
(R) :The molality of a solution does not depends on temperature whereas molarity depends.

 $$\begin{gathered} \mathrm{We} \mathrm{know},\frac{\mathrm{Mass} \mathrm{of} \mathrm{solvent}}{\mathrm{Volume} \mathrm{of} \mathrm{solution} }<1 \\ \mathrm{Mass} \mathrm{of} \mathrm{solvent} < \mathrm{Volume} \mathrm{of} \mathrm{solution} \\ \frac{1}{\mathrm{Mass} \mathrm{of} \mathrm{solvent}}>\frac{1}{\mathrm{Volume} \mathrm{of} \mathrm{solution}} \\ \mathrm{Molality} > \mathrm{Molarity} \end{gathered}$$
Molality is inversely proportional to weight of solvent, where weight is independent of temperature.
Molarity is inversely proportional to volume, where volume depends on temperature thus molarity depends to temperature.
Hence, correct option is: (B) Both (A) and (R) are true and (R) is not the correct explanation of (A)