Dicken's object of social criticism which is referred in this excerpt is that, the system of education which treats children as if they are machines. It is shown in the novel that only the society but it did not focus on its emotional context.
Teachers only cared about the results of the input which they gave and if is not corrected then the students will bring to the society.
This is the reason why there is a big gap which is between the poor and the rich. Rich believes that the poor can make it if they can strive harder.
I think it is Serious. He needs to be serious about getting his School to accept uniforms or reject them. If he was humorous the School wouldn't take him seriously, if he was demanding the school would probably not want to be ordered to do something by one of their students. And if he was pleading it may work but over all him being serious about the topic would lead him to success.
The sentence that contains an interjection is " Hurrah! I've finally found the answer." The correct answer is D. An interjection is an exclamation, in a part of speech.
By giving practical assynments to the students and then, by doing with the students together. by appreciating by showing directions; by motivating students etc.