Please help me with endothermic vs exothermic.

Question

Which of the following processes is endothermic?

A. H₂O(g)  H₂O(l)

B.O₂(g) + 2 H₂(g)  2 H₂O(g)    

C. 3 O₂(g) + 2 CH₃OH(g)  2 CO₂(g) + 2 H₂O(g)

D. H₂O(s)  H₂O(l)

Answer 1

D. H₂O(s)  H₂O(l)

Because you have to add heat (endothermic) to turn a solid into a liquid, this would be an endothermic reaction.