Answer: d. the increasing fragmentation of the narrator’s sense of self.
The fragmented journal entries most likely symbolize the increasing fragmentation of the narrator's sense of self. As the narrator has been locked for so long, with no other outlet than that of her journal, this is likely to be the best account of how the narrator feels about her situation. As the journal becomes more fragmented, we can assume that the author becomes more confused about herself. We know that she is deprived of interaction with the world or intellectual stimulation. This forces her to lose her sense of self, and in time, her sanity.