The correct option is B 100∘ C
Heat required to melt 1gof ice at 0∘ C is 80 cal.
Heat required to convert 1g of water at 0∘ C into 1g of water at 100∘C=1×1×100=100=100cal.
Heat required condensing 1g of steam = 1 × 540 cal = 540 cal
Clearly, whole of steam is not condensed. So, temperature of the mixture is100∘ C.