There are two processes - let us call them P and Q.
The similarity between P and Q is that both represent a change from liquid state to gas state.
The difference is that in P, change to vapour occurs only at the liquid surface; in Q, it occurs throughout the liquid.
What are P and Q respectively...


A - Condensation and Evaporation
B - Evaporation and Boiling
C - Boiling and Sublimation
D - Sublimation and Condensation