Read the following passage excerpt, then answer the question. --- PASSAGE 1 — Literary Fiction For three decades, Marcus operated the clocktower at the center of Millfield. Every morning at precisely six o'clock, he ascended the spiral oak staircase, carrying his brass oil can and velvet polishing cloth. To the townspeople below, the steady chime of the bells was as dependable as the sunrise. Yet inside the tower, Marcus felt the slow erosion of time in his own joints. His apprentice, Clara, had recently begun adjusting the heavy pendulum weights without his supervision. Watching her balance on the narrow iron gantry, Marcus recognized that the machinery had outlasted generations of keepers and would surely outlast him. Rather than fear his impending retirement, he felt a quiet relief that the rhythm of the town would remain unbroken. --- Which sentence best states the central theme of the passage?