I think you will find evidence for answer choice D in paragraph three. Take a look at line 37: "Okapis never eat one plant to the exclusion of others; even where preferred foliage is abundant, okapis will leave much of it uneaten, choosing to move on and sample other leaves."
The okapis do not finish one type of food before going on to the next. Instead, they sample a wide variety of leaves. This is comparable to the newspaper reader who samples different stories without reading them completely.
The question stem mentions the eating behavior of these animals, so make sure you direct your attention to the paragraph in which eating behavior is discussed. Just about all of the information we need to answer this question can be found in the sentence I copied above.
