Can someone please help me? :(

A) Nighttime was approaching.

Explanation:

Nighttime was insinuated, but not bluntly or plainly shown.  Implicit means "Implied though not plainly expressed."  SO if we look at the passage and the multiple-choice questions we see that B, C, and D, were all plainly expressed.  They were given a signal, as well as were "explicit" because they didn't hide any information.  The only information we have that "nighttime was approaching" would be that the "sky was getting dark."

samuel gompers was an extremely important person in the american labor movement, being him an employee all his life he devoted himself to fight for the rights of his pairs, he believed they all had the right to have better thing and that they all were working for them but the factory workers were greedy, ambitions and socialist people for him who he didn't have a good concept of.

he gave so many speeches and led so many strikes and protest to fight for equality which he considered employers didn't want to accept, so he had an absolutely negative opinion of them.