Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : At 10⁰C, the density of 5 M solution of KCl (atomic mass of K and Cl are 39 and 35.5 repectively) is x g.mL^-1 .The solution is cooled to -21⁰C. The molality of the solution will remain unchanged. 

Reason R : The molality of a solution does not change with temperature as mass remains unaffected with temperature.

In the light of the above statements, choose the most appropriate answer from the options given below.