You need to write the main idea of each paragraph of the story and if all the mean ideas are about the same topic then you got the main or central idea of the story.
Thesaurus is the tool where you can find synonyms for a word, and even antonyms.
Although you can find synonyms in a regular dictionary as well, thesauri are better when it comes to that.
I don’t really understand what you have to do
In the Emancipation Proclamation, issued by the President of the United States, Abraham Lincoln, in the year of our Lord 1863, "suitable condition" refers to option 3. that those persons who were previously enslaved must have displayed the same minimum requirements for service in the armed forces as those who had not been enslaved.
In the Emancipation Proclamation, President Lincoln, states that " ...I do order and declare that all persons held as slaves within said designated States, and parts of States, are, and henceforward shall be free..." and those who are in good condition to serve the armed forces of the United States will be received there.
The correct answer is the C. Constitution for the United States of America.
Explanation
A preamble is a part of the introductory part of a law in which the reasons for which it originated are contextualized and exposed. According to the foregoing, the preamble of the United States allows us to know the context in which the Constitution originated and its purpose as a normative framework of a nascent nation. So the correct answer is the "C. Constitution for the United States of America" because fragment clearly establishes the purpose of this document.