1. Sublimation occurs only above the line and melting occurs only below the line
2. Melting occurs only above the line and sublimation occurs only below the line
3. Above the equilibrium line, the amount of accumulation exceeds the amount lost by various processes
4. Air temperatures are below freezing below the line and above freezing above the line
“The equilibrium line of a glacier is the location where winter accumulation of snow is equal to the summer loss.”
So, statement 3 is the only true statement here.