To Exhibit
To Demonstrate
する verb
Departure and brandish this thing. This means you're sending something out to show to everyone. That's why this is to exhibit or to demonstrate (because when you brandish, and send it out to show, you're demonstrating it!).
はっきする
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own. The はつ becomes はっ, though.
問題解決にリーダーシップを一番発揮していたのは誰ですか。
Who demonstrated the most leadership in solving the problem?