Walt Whitman's poems, such as “Crossing Brooklyn Ferry," made him a pioneer of O rhythmic verse.
O formal verse.
O free verse.
O repetitive verse.

Free verse.

Explanation:

Walt Whitman is an American poet, who is famously known as the 'Father of free-verse.' He, now, is considered to be the most celebrated poet of his time, but his poetries were scorned and thought to be disgraceful during his lifetime.

While writing poetry, he broke the rules of convention and wrote in 'free-verse.' The first collection of his poems were published by him under the title 'Leaves of Grass' in 1855.

His other poems, such as 'Crossing Brooklyn Ferry', which descrbes thhe speaker's daily journey from Brooklyn to Mahattan on a ferry, was also written using 'free verse.'

Free-verse is a form of poetry, in which verses are written in irregular form, rhythm, and length.

Thus the correct answer is the third option, Free-verse.

the correct answer is   d. a picture depicting people applauding a country's leader.