Question

During the melting of a slab of ice at $273\text{K}$ at atmospheric pressure:

Answer 1

During the melting, of a slab of ice at $273\text{K}$ at the atmospheric pressure, the ice is about to convert into the water on a slight increase in temperature. The internal energy of water is higher than that of ice. As a result, the internal energy of the ice-water system increases.
Also, the volume decreases. So work done i.e. -$P\Delta V$ become positive

Hence, Option $\left(B\right)$ is the correct answer.