Final answer:
One possible theme of the poem is the importance of enjoying life, as reflected by the imagery of cherry blossoms and the contemplation of the speaker's own mortality.
Step-by-step explanation:
The theme of the poem hinting at the transient nature of life and the importance of cherishing the beauty around us is best represented by option D: Life is short, so it's important to enjoy it as much as possible. The poem reflects on the brevity of human life — 'threescore years and ten' signifies a lifespan of seventy years, with 'twenty will not come again' emphasizing the passage of youth. The poem's speaker resolves to appreciate the cherry blossoms throughout the fifty springs they have left, symbolizing the need to savor life’s fleeting moments.