From what I’ve seen I think the mood is dark. It’s about a father and his son and his alcoholic father.
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.