Workers with similar skills in similar jobs established to work towards higher wages and shorter work days. a. trade unions c. the nativists b. strikes d. the know-nothing party

A. Trade unions   
Let's look at the options and see what does and does not make sense. 
 a. trade unions 
 * This is a labor union of people in related crafts unlike a general union, or a union of all workers in a specified industry. This looks to be the correct answer, but let's look at the other options to be sure. 
 b. strikes 
 * This is a means to attempt to force management to comply with labor's demands. It's a tool used by many unions, but doesn't make sense in the context of the question given. So this is a bad choice. 
 c. the nativists 
 * This is a political movement aimed at limiting immigration. So this also doesn't make sense in the context of the question and is also a bad choice. 
 d. the know-nothing party
 * The know-nothing party is a political party of nativists. And since option "c" didn't make sense, neither does this option. So it's a bad choice.

Answerpromissory restraints;

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