Final answer:
The phrase "heaved up" suggests a significant effort to move something heavy, which leads to the conclusion that the last word is metaphorically heavy and difficult to lift, emphasizing the effort needed to express a burdensome concept.
Step-by-step explanation:
The phrase "heaved up" used by an author typically implies a significant effort to move something that is perceived as being very heavy or burdensome. This could be a physical object, an emotional weight, or a difficult idea. In the context of the provided question, choice A) The last word is heavy and difficult to lift seems most appropriate if the last word of the passage or poem is meant to emphasize the difficulty of communicating a particularly heavy or burdensome concept. This would align with the physically straining connotation of the phrase "heaved up." To a lesser extent, C) The last word is causing physical strain could also apply if it is understood that the strain comes from the difficulty of expressing the word or concept, rather than physical weight alone.