Consider the drying operation shown in the figure below for a solid loading (dry basis) of $50 \text{ kg/m}^{2}$ with a constant drying rate of $5\: \text{kg/m$^{2}$.h.}$ The falling rate of drying is linear with moisture content..

The drying time(in hrs) required to reduce an initial moisture content of $25\%$ to a final moisture content of $2\%$ is

1. $1.55$
2. $1.75$
3. $3.25$
4. $4.55$