Answer:
B). And I say it is as great to be a woman as to be a man.
Step-by-step explanation:
Whitman is one of the most loved and acknowledged American poets due to his ideals of democratic poetry, individualism, etc. In 'Song of Myself', he acknowledges and celebrates the affinity of mankind and democracy as he felt that all humans are common by their soul.
As per the question, the line that advocates Whitman's idea of every human being equal before the poet is displayed through option B as mentioned above. This line indicates his ideal of equality that every human being is equal before a poet regardless of gender or sex. Thus, option B is the correct answer.