A concrete statement can be considered as a 'solid' statement. This means that the sentence must contain hard facts to manifest the credibility of the statement. As much as possible, you give specific examples and provide evidence for this. From the choices, the answer would be D.
C- By focusing on topics that are controversial
The answer is c because it uses the pronoun you
The theme being presented was think twice before you say anything. I think this was the theme because, the grasshopper could not be responsible of getting food, and the ants did not want to give their food. So the theme was think twice before you say anything.