radio wave / mobile phone signal / (slang) nonsense produced by a mentally unsound person, who is termed a 電波(でんぱ)系(けい) (denpa-kei, “radio-wave-type”) person

社用: company business / 斜陽: setting sun

sweetfish

Onomatopoeia for the sound effect associated with a correct answer. / Onomatopoeia for the doorbell ringing.