Answer:
C). It forces readers to "grapple" with their own mortality.
Explanation:
As per the question, option C exemplifies the idea that King elaborates in 'Danse Macabre'. The king's idea is to 'enforce the readers to 'grapple' or combat with their own mortality or transience' and imply that no one is going to do that for you which is reflected by Riya's advanced efforts despite her 'aching legs' to reach 'jutting rocks' even though it was 'beyond her grasp'. The king's primary concern is to motivate and encourage the readers to not bend knees before 'brevity of life' and show some courage to combat their own mortality. Thus, option C is the correct answer.