For one mole of a van der Waals gas with $$b = 0$$, the plot of $$PV$$ versus $$\frac{1}{V}$$ at 298 K gives an intercept of 24.4 L atm K $$\text{mol}^{-1}$$ and a slope of $$-2.5\ \text{L}^2\ \text{atm}\ \text{mol}^{-2}$$. The value of the van der Waals constant $$a$$ is

A

$$12.5\ \text{L}^2\ \text{atm}\ \text{mol}^{-2}$$

B

$$5.0\ \text{L}^2\ \text{atm}\ \text{mol}^{-2}$$

C

$$4.5\ \text{L}^2\ \text{atm}\ \text{mol}^{-2}$$

D

$$2.5\ \text{L}^2\ \text{atm}\ \text{mol}^{-2}$$