Conservatives and liberals have very different views on healthcare reform. a news station places a story featuring the conservative point of view at the top of its newscast, while placing a short story on the liberal point of view at the end. this is an example of bias by placement bias by spin bias by omission bias by labeling

A. Bias by placement, because bias by labeling would be something to the effect of calling the liberals point of view  uneducated, or giving there view some negative label, bias by omission would mean completely ignoring the other side, and not covering it at all, whereas all the other ones don't really fit, bias by placement is something to the effect of airing one side in the morning, while everyone is watching, and airing the other one after everyone is asleep, which is what is done here, which we know by the sentence "liberal point of view at the end."