THe heart represent guilt because it was all in his head, and the clock represents death approaching, hope this helps.
A narrator can write from different points of view, mainly first person or third person. Choosing the point of view is a big deal for an author, because the perspective from which a novel is narrated has a big impact on a reader's experience.
Since this is an open question with no choices, I am answering with what I think will best fill in the blank. Note: I do not know exactly what answer they are looking for.
The best answer is: REM
REM is the stage of sleep where dreaming occurs. REM stands for Rapid Eye Movement. Exactly as the title says, REM sleep is characterized by fast back and forth movement of the eyes.