Which word would indicate a future time reference?

The word "later" is an effective indicator of a future time reference. It explicitly suggests that something will occur at a subsequent time, indicating a delay or a point in time that follows the present. This word is often used to describe actions or events that are planned or anticipated to happen after the current moment, distinguishing it from terms that refer to the present ("now") or the past ("then").

In contrast, "clearly" serves as an adverb to express certainty or transparency, rather than time. "Now" relates directly to the current moment, while "then" typically refers to a past point or event. Therefore, "later" is the sole option that distinctly conveys a future timeframe.