Answer: D) its constancy in contrast to the rapid changes the speaker undergoes.
Step-by-step explanation: In the given poem "Bright Star" by John Keats, we can see the description of a star as eternal, sleepless ("And watching, with eternal lids apart, Like nature's patient, sleepless Eremite") and the author contrasts this idea with the changes and movement of his life ("The moving waters at their priestlike task Of pure ablution round earth's human shores"), he makes clear that despite the rhythm and changes of his life, the star (and the nature) is constant and unchangeable.