A Plot of the Temperature Versus the Energy Per Kg $\degree$

A plot of the temperature versus the energy per kg added to a piece of ice as it goes from below freezing at - 10 $\degree$ C to becoming steam at 110 $\degree$ C consists of straight lines,some horizontal and some with an upward slope.What do the upward slopes represent?

A) specific heats
B) reciprocals of specific heats
C) latent heats
D) reciprocals of latent heats