Step 1: Start from the ideal behaviour of a dilute solution, which mirrors the ideal gas law \(PV = nRT\). For osmosis, the solute particles behave like a gas exerting pressure, so \(\pi V = nRT\).
Step 2: Divide both sides by \(V\): \(\pi = \dfrac{n}{V}RT\).
Step 3: The ratio \(\dfrac{n}{V}\) (moles per unit volume) is the molarity \(C\) of the solution. Substituting gives \(\pi = CRT\).
Step 4: Thus the working formula involving concentration is \[ \boxed{\pi = CRT} \] confirming choice (i). The other choices do not reduce to the van't Hoff relation.