Answer: 4. The narrator’s mood is determined by the state of the relationship with his love.
Step-by-step explanation: The central idea of the given stanzas from the poem "Ballad" by Paul Laurence Dunbar is that the narrator's mood is determined by the state of the relationship with his love. When he is sure that his love is true, he thinks the day is fair, the sky is blue, the flowers are beautiful, etc, but when he finds that his love is false, he sees the day as dark, he doesn't hear the lark, and he is very sad. So the correct answer is option 4.