The vapour pressure is least for

We know that

Vapour pressure decreases with an increase in no. of solute particles.

Therefore, the solution having a greater number of solute particles has less Vapour pressure.

Since, $0.3 \mathrm{m}$ urea has a greater number of solute particles as molality is directly proportional to no. of moles.

Therefore, $0.3 \mathrm{m}$ urea has the least vapour pressure.

Hence, option(d) is correct.