Noun, する verb, and の adjective
しつもん
彼はある観客からの予想外の質問にたじろいだ。
He flinched at the unexpected question from an audience member.
A quality problem is worth a question. A low quality problem however... don't ask the question. There are stupid questions, after all.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.