Reviewing of your notes should be your primary concern, then refer to subtle differences?
The answer is C. At first the child misjudges the elderly neighbor when he fears her, and is happy with their new friendship when she helps him.
A has misjudgment but no happiness.
B doesn't match at all
D doesn't say that the rivals misjudged their rivalry or were happy at any point.
(A) Attaching importance to wealth