Answer:
-D. The poem repeats the phrase "Take up the White Man's burden" as a sort of call to action, thus contributing to the encouraging, prideful tone.
Explanation:
Rudyard Kipling's poem "The White Man's Burden" was written after the Spanish-American War where the US acquired the Philippines. This poem was a sort of call for the "white man", i.e. America, to go and "civilize" the natives, in this case, the people in the Philippines.
Kipling believes that it is up to the American people to go and 'civilize' the other inferior people, just like the British had done to the colonies in America. He repeatedly used the phrase "Take up the White Man's burden" to encourage and call the US to do the job of 'helping' these people. This repetition contributes to encouraging them in doing the 'good deed' but it also contains a prideful tone in that it deemed itself (the US? Americans) as more superior to the newly acquired island.
Thus, the correct answer is option D.