For I have learned/To look on nature, not as in the hour/Of thoughtless youth; but hearing oftentimes/The sad, still music of humanity” ?

A. The poet’s changing relationship to nature as fount of meaning and significance
B. The falsity of human art as opposed to the immediate truth of nature
C. The failure of the poet when a youth to imagine his future
D. The utter rejection of youthful folly in favor of mature rationality