Answer and explanation:
Letter C is indeed the one that supports the theme "Having a mixed heritage can lead to mixed feelings". When discussing heritage, it is very common to use the word "blood" to refer to one's ancestry. We often hear people say they have Italian blood, for instance, and use that expression to justify a behavior, a personality trait, or an eating habit. When the speaker says, "only one part of my blood loves that memory", we can assume that having a mixed cultural heritage causes him/her to struggle. Maybe that memory refers to something that is acceptable in one culture but not in the other. Maybe the speaker has learned a new way to see things and this perspective goes against inherited customs.