a. The king is the one who uttered the line "One must require from each one the duty which each one can perform". Each one should perform a duty. Each one should cooperate in order to have the duty be done.
b. The meaning of the line "It is much more difficult to judge oneself that to judge pthers" is that it is difficult to judge yourself. If you make decisions, of course, you think the right one. But if you think of it, it's hard to judge it because you made the decision that you think the right one. While in others, if you think that thir decision is wrong, of course, you will judge them that their decision is wrong.
c. The line "Conceited people never hear anything but praise" mens that a person that is conceited only hars the words that are favorable to them. Yes, because these people do not accept criticism.
d. Drinking is not the right way to forget. It can really relate to the line "I am drinking so that I may forget". These are the lines that usually come out to people that has problems.
e. The businessman wanted to become rich because he wanted to buy all the stars in the universe. Some people just wanted money because they wanted to buy the things they wanted even if it's not important.
f. The meaning of the line "There is nothing to understand. Orders are orders" is that there's no need to understand, just obey what was ordered. But, in my opinion, you need to understand first before obeying the orders, in order not to make mistake.
g. The little prince perceive the character of the lamplighter as he is the only person he could make friends of, but because of his small planet, he can't live there. He also loves to sleep, but there is no place for his laziness in his planet. Yes, because the lamplighter's work is to turn on & off his lamp whenever his planet got a complete turn. It's really a terrible profession for lazy persons.
h. The geographer represents the truth about the adults that they have thier job, but they are not coing it properly. They are just known by "name" not by their deed. Some people are like the geographer, they are only known by "name" not by their deed.
i. He described the planet earth a planet full of grown-ups like what the little prince's have met. I think the pilot was true, because as I read the book and the little prince always describes the character of every grown-up he met, I really remembered the people I knew before.
j. The snake thinks that he/she was very powerful & smart.
k. The truth is that some people have nothing to do at all. Some only observe other people without doing any response or action.