: 3-nen E-gumi Utatan (Mai Fuchigami, Aya Suzaki, Nobuhiko Okamoto, Ryota Osaka, and Shintaro Asanuma).
: Season 2, Opening 1 (technically the 3rd opening of the series).
If you are looking for or instrumental versions, some creators provide downloads for these specifically, such as this Trumpet Sheet Music available on YouTube.
: You can stream the full version of "QUESTION" for free on SoundCloud .
The 3rd opening theme for Ansatsu Kyoushitsu (Assassination Classroom) is titled , performed by 3-nen E-gumi Utatan (a group consisting of the main voice actors).
: Official and high-quality creditless versions of the opening are available on YouTube .