The correct ingredient with 正解
Kanji Explanation: Separating and understanding with 解

Takagi challenges Nishikata to guess what ingredient is inside a riceball in her lunch box. Seeing a bit of salmon from the other riceball, Nishika goes with salmon as his guess.
- 高木:
- 「正解はウメでした。」
- “The correct answer was apricot.”
正解
Key Points
正解
( = “correct answer”正
( adds the idea of correctness, and 解( is the answer or solution.Here it means the one answer that was actually right in Takagi’s guessing game.
Why は is used after 正解
( は sets the answer as the topic before telling what it was.