What does King mean by “isness” of humanity’s present nature? (line 37)

By 'isness' of humanity's present nature, King meant moral incapibility of humankind to do what is morally obligatory or morally right.

Explanation:

Martin Luther King was bestowed with the Nobel Prize on 11th December, 1964. King was the leader of the Civil Rights Movements, although the movement was sundry to bestow one person the Nobel Prize.

In his speech, he began with reflecting great grief on the loss of lives during this movement. He said

'I refuse to  accept the idea that the “isness” of man's present nature makes him morally incapable of reaching up  for the eternal “oughtness” that forever confronts him.'

The term 'isness' refers to the state of being or existence. By 'isness' of humanity's present nature, King meant to say that he refuse to accept that humankind is morally incapable of doing what is morally right or obligatory. The 'existence' of man's present nature of inability to do what is morally right is unacceptable in the eyes of King.

the progressive era is a period of widespread social activism and political reform across the united states that spanned from the 1890s to the 1920s.[1] the main objectives of the progressive movement were eliminating problems caused by industrialization, urbanization, immigration, and political corruption.

the movement primarily targeted political machines and their bosses. by taking down these corrupt representatives in office, a further means of direct democracy would be established. they also sought regulation of monopolies (trust busting) and corporations through antitrust laws, which were seen as a way to promote equal competition for the advantage of legitimate competitors.

many progressives supported prohibition of alcoholic beverages, ostensibly to destroy the political power of local bosses based in saloons, but others out of a religious motivation. at the same time, women's suffrage was promoted to bring a "purer" female vote into the arena.a third theme was building an efficiency movement in every sector that could identify old ways that needed modernizing, and bring to bear scientific, medical and engineering solutions; a key part of the efficiency movement was scientific management, or "taylorism".

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i think the answer is   b.