The knights of labor and the american federation of labor developed in response to the
a
increased need to protect worker interests
b decreased power of political machines
cincreased demand for skilled workers
d decreased profitability of the agricultural sector

The Knights of Labor and the American Federation of Labor developed in response to the increased need to protect worker interests .

Explanation:

During the period of industrialisation there was widespread exploitation of labour force in America. The workers were working in the worst condition and their wages are not adequate to the hours of work they put in.

And employment of child labour was also in practice during this period. So to protect the employees from this unfair practices first American labour union was started in the year 1869 and the name of the union is Knights of Labour established by its first leader Uriah Smith Stephens.

In the subsequent year another labour federation called American Federation of Labour was established in 1886, at Ohio, Columbus. Both the federation fought for the welfare of American workers.

to protest slavery i would think it would be a