$\mathrm{M}=$molarity of the solution

$\mathrm{m}=$ molality of the solution

$\mathrm{d}=$ density of the solution (in g. ${\mathrm{ml}}^{-1}$ )

${\mathrm{M}}^1=$ gram molecular weight of solute

Which of the following relations is correct

Given Data: It is asked in the question to select the correct relation between entities such as molarity, molality, density, and molecular weight.

Concept Used: Definitions of molarity, molality, density, and molecular weight,

Detailed Solution:

The concentration of a solution can be expressed in various forms, two such ways  are molarity and molality. The mathematical relation between these two quantities can be reosented using the expression:

$m=\frac{1000M}{1000d-M{M}^1}$

Where each symbol has the same meaning as provided in the question. 

Hence the correct option is C.