The correct answer is B. There are many variations in the sky throughout the day.
Explanation
The central theme of the poem is the diversity that the sky has during the day. Initially, it highlights colors such as black at dusk, pink at dawn, blue, among others. On the other hand, he uses the metaphor to associate visual phenomena such as sunrise, clouds, and the flight of birds with fantastic events, for example:
"Then one by one puffy clouds dot the sky
Joining and forming dreamy myth-bred shapes
Of lions that paw the earth down below
And dragons that hide beneath their cloudy capes .. "
It is possible to infer that the main purpose of the author is to highlight the different changes that the sun has during a day according to the state of the weather (sunny or rainy) or the time of day (morning, afternoon, or night). So the correct answer is B. There are many variations in the sky throughout the day.