What is the message the author wants us to know in the book the giving tree

1) As a symbol of mother-child relationship.
As a mom who always eyed her share of her son's chocolate, my comment on this is , No comment! See, you can make a point without using cliches like stereotyping.

2) A symbol of our connection with God.
It depends on what religion you belong to. In many religions, the relationship between God and humans is much more complex.

3) As a religious parable. Then, most children's stories can be reduced to parables and most of them will make better parable than this.

4) An adult satire in Swiftian style and not a children's book at all.
The real satire is how we reject the simple and go for the complicated one. No wonder, modern life is so complicated.

5) A commentary on codependency 
It's a sad book any way but there is simplicity in this sadness. I don't want to make it depressing..

6) An allegory for the social welfare state and/ or late stage capitalism.
This is the most interesting one undoubtedly but probably already redundant. Most of the world has accepted that the path lies somewhere in between.

7) Our relationship with mother Earth.
An extension of No. 1 , this is my second favorite. If there is any example of one way, selfless giving , this is it. The book was published before I was born , so I don't know how apt this symbol was at that time but for today's world it has a relevant message.

8) Lost joys and simplicity of childhood and complications of adult life.
Finally, I judge a book not only by what it makes me think but also how it makes me feel.  This is what Shel's simple words and simple drawings have made me feel : the complications of adult life created by our mindless pursuit of materialism and the contrast it creates with the simple pleasures of childhood is what it is all about.

the answer should be d) he was one of those young thousands who greeted the war with a certain amount of relief, welcoming the liberation from webs of tangled emotion" since it is the best option because it shows his desire to free himself.

hope this answer you! have a great day.