The correct option is A life is a fairy tale
Option A: that life is a fairy tale
As mentioned in this line, "Most often, in children's storybooks and through our parents we see
only part of the truth. We learn that life is about goodness and success." we are told as children that life is all about the good. This is the same idea used in fairy tales, that everything has a 'happy ever after'.
Hence option A is correct.
Option B: This line 'we may face failure' is what we should be told, as opposed to the given sentence 'we should not be told'.
"We are not told that we have to face failure and sometimes we stumble and fall down."
Hence option B is incorrect.
Option C: This line, too, is what should be told to us as children, as opposed to what should not be told.
Option D: Similarly, this line states what should be told, "We are not assured that it is not the result that is important but our
efforts to make the best of things that make us successful."
Hence options B, C and D are incorrect.