The osmotic pressure of 5% aqueous solution of sugar (mol. Mass 342) at 15°C is

Mass of Solution = 100 g
The density is 1 g/ml.
100 ml = 0.1 liter is the solution's volume.
$$\begin{gathered} \mathrm{Sugar} \mathrm{moles} =\frac{5}{342} = 0.146 \mathrm{mole} \\ \mathrm{Osmosis} \mathrm{pressure}\left(\mathrm{\pi }\right)= \mathrm{CRT} \\ \mathrm{Osmotic} \mathrm{pressure} = \frac{\mathrm{nRT}}{\mathrm{V}} = \frac{0.0146\times 0.08206\times 288}{0.1}= 3.45 \mathrm{atm} \end{gathered}$$
 

Therefore, the correct option is B 3.45 atm