With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: On 25 May 1997, Bohumil Šole, a scientist who claimed to have been involved with inventing Semtex, committed suicide at a spa in Jeseník by blowing himself up with explosives. Šole, 63, was being treated there for psychological problems. Chemical residue at the scene revealed that he had indeed used Semtex. Twenty other people were hurt in the explosion, while six were seriously injured. According to the manufacturer, Explosia, he was not a member of the team that developed the explosive in the 1960s.
text_B: Given the amount of reliable evidence (or lack thereof) surrounding the explosion, is it possible (however unlikely) that Bohumil Šole's death could have been a tragic accident rather than a deliberate act?
NO.