Fitzgerald's message about the American Dream is that it is all disillusionment, meaning fake or not real. In his novel The Great Gatsby, Gatsby throws disillusionment all over the place. He seems like he has friends but when his time comes to have a funeral only one person calls and the person calling just wants his clothing back from Gatsby.
A system means a group of things that are together
The answer is A, look up the definition and you will see why.
Make eye contact around the room, be enthusiastic, dont slouch, never have back towards audience
“i can drink that soda straight as if it was water” means that he/she can drink that soda like they drink water. with the same reaction in easier words